#include <iostream>
#include <vector>

using namespace std;

struct Point
{
    int x;
    int y;

    bool is_equal(const Point& other) const
    {
        return (x == other.x) && (y == other.y);
    }

    bool operator==(const Point& other) const
    {
        return is_equal(other);
    }

    //调试函数
    void tostring() const 
    {
    std::cout << "(" << x << ", " << y << ")";
    }

    
};
 
const int INF = 11;

struct M
{
    int a;
    int b;
    int x = a + 1;
    int y = b + 1;
    vector<vector<int>> m = vector<vector<int>>(x,vector<int>(y,INF)); // map
    // vector<vector<int>> m(x,vector<int>(y,INF));

    void tostring() const
    {
        for (int i = 0; i < x; i++)
        {
            for (int j = 0; j < y; j++)
            {
                std::cout << m[i][j] << ' ';
            }

            std::cout << '\n';
            
        }
        
        
    }
};
auto get_banned_points(Point horse)
{

    /** To get the control points of horse
     *  @param Point horse
     *  @return vector<Point> out
    */
    

    // Point offs[] = 
    // {
    //     {-2, 1}, {-1, 2}, {1, 2}, {2, 1},
    //     {-2, -1}, {-1, -2}, {1, -2}, {2,-1},
    // };

    // vector<Point> offsets(offs,offs+8);

    //偏移量
    vector<Point> offsets = 
    {
        {-2, 1}, {-1, 2}, {1, 2}, {2, 1},
        {-2, -1}, {-1, -2}, {1, -2}, {2,-1},
        {0, 0},
    };

    vector<Point> out;

    for (const auto &p : offsets)
    {
        out.push_back
        ({
            horse.x+p.x, horse.y+p.y
        });
    }
    

    return out;

}

auto set_banned_points(const M &_m, const vector<Point> &_banned_points)
{
    /**
     *  to set banned points to the map
     *  @param M map, vector<Point> &_banned_points
     *  @return M new_map
     */

    auto out = _m;

    //out.tostring();

    cout << '\n';

    for (auto &&p : _banned_points)
    {
        if (
            ( p.x >= 0 ) && ( p.y >= 0)
            && (p.x <= _m.x) && (p.y <= _m.y)
        )
        {
            out.m[p.x][p.y] = -1;
        }
        
    }
    return out;
    
}

static int cnt; //路线计数

void dfs( M &_m, int current_x, int current_y)
{
    /**
     * 深度优先算法
     * @param M map, Point current_point
     * @return count
     */

    //判断是否越界
    if (
        (current_x > _m.x) || (current_y > _m.y)
        || (current_x < 0) || (current_y < 0)
        )
    {
        return;
    }
    

    //达到终点的情况
    if (
        (current_x == _m.x)
        && (current_y == _m.y)
    )
    {
        cnt ++;
        return;
    }

    //碰到控制点的情况
    if (_m.m[current_x][current_y] == -1)
            return;
    
    // int cnt = 0;

    // cnt += dfs(_m,current_x+1,current_y);
    // cnt += dfs(_m,current_x,current_y+1);

    dfs(_m,current_x+1,current_y);
    dfs(_m,current_x,current_y+1);

    // return cnt;
    
}

int main()
{
    int bx, by, hx, hy; //B点坐标 马坐标
    //int cnt;
    

    
    
    vector<Point> banned_points;

    //cin >> bx >> by >> hx >> hy;

    // input test data
    bx = 6;
    by = 6;
    hx = 3;
    hy = 3;

    Point B = {bx, by}; //B点
    Point H = {hx, hy}; //马

    M m = {bx, by}; //地图

    banned_points = get_banned_points(H);
    m = set_banned_points(m, banned_points);
    m.tostring();

    //cnt = dfs(m,0,0);
    dfs(m,0,0);

    cout << cnt;

    




    // TEST CODE
    // M map = {10, 10};
    // map.tostring();


    /** 这是象的代码
    for (int i = 0; i < 3; i++)
    {
        for (int j = 0; j < 3; j++)
        {
            banned_points.push_back({
                ( (hx-2) + (i*2) ),
                ( (hy-2) + (j*2) ),
                });
        }
        
    }*/
    

   //输出点
    // for (const auto& p : banned_points)
    // {
    //     p.tostring();
    //     cout << ' ';
    // }
    


    // for (int i = 0; i <= bx; i++)
    // {
    //     for (int j = 0; j <= by; j++)
    //     {
    //         Point current_point = {i, j}

    //         auto it = find(
    //             banned_points.begin(),
    //             banned_points.end(),
    //             current_point); 
            
    //         if (it != banned_points.end())
    //         {
    //             break;
    //         } 
            
            
    //     }
        
    // }
    






    return 0;
}
#include <iostream>
#include <vector>

using namespace std;

struct Point
{
    int x;
    int y;

    bool is_equal(const Point& other) const
    {
        return (x == other.x) && (y == other.y);
    }

    bool operator==(const Point& other) const
    {
        return is_equal(other);
    }

    //调试函数
    void tostring() const 
    {
    std::cout << "(" << x << ", " << y << ")";
    }

    
};
 
const int INF = 11;

struct M
{
    int a;
    int b;
    int x = a + 1;
    int y = b + 1;
    vector<vector<int>> m = vector<vector<int>>(x,vector<int>(y,INF)); // map
    // vector<vector<int>> m(x,vector<int>(y,INF));

    void tostring() const
    {
        for (int i = 0; i < x; i++)
        {
            for (int j = 0; j < y; j++)
            {
                std::cout << m[i][j] << ' ';
            }

            std::cout << '\n';
            
        }
        
        
    }
};
auto get_banned_points(Point horse)
{

    /** To get the control points of horse
     *  @param Point horse
     *  @return vector<Point> out
    */
    

    // Point offs[] = 
    // {
    //     {-2, 1}, {-1, 2}, {1, 2}, {2, 1},
    //     {-2, -1}, {-1, -2}, {1, -2}, {2,-1},
    // };

    // vector<Point> offsets(offs,offs+8);

    //偏移量
    vector<Point> offsets = 
    {
        {-2, 1}, {-1, 2}, {1, 2}, {2, 1},
        {-2, -1}, {-1, -2}, {1, -2}, {2,-1},
        {0, 0},
    };

    vector<Point> out;

    for (const auto &p : offsets)
    {
        out.push_back
        ({
            horse.x+p.x, horse.y+p.y
        });
    }
    

    return out;

}

auto set_banned_points(const M &_m, const vector<Point> &_banned_points)
{
    /**
     *  to set banned points to the map
     *  @param M map, vector<Point> &_banned_points
     *  @return M new_map
     */

    auto out = _m;

    //out.tostring();

    cout << '\n';

    for (auto &&p : _banned_points)
    {
        if (
            ( p.x >= 0 ) && ( p.y >= 0)
            && (p.x <= _m.x) && (p.y <= _m.y)
        )
        {
            out.m[p.x][p.y] = -1;
        }
        
    }
    return out;
    
}

static int cnt; //路线计数

void dfs( M &_m, int current_x, int current_y)
{
    /**
     * 深度优先算法
     * @param M map, Point current_point
     * @return count
     */

    //判断是否越界
    if (
        (current_x > _m.x) || (current_y > _m.y)
        || (current_x < 0) || (current_y < 0)
        )
    {
        return;
    }
    

    //达到终点的情况
    if (
        (current_x == _m.x)
        && (current_y == _m.y)
    )
    {
        cnt ++;
        return;
    }

    //碰到控制点的情况
    if (_m.m[current_x][current_y] == -1)
            return;
    
    // int cnt = 0;

    // cnt += dfs(_m,current_x+1,current_y);
    // cnt += dfs(_m,current_x,current_y+1);

    dfs(_m,current_x+1,current_y);
    dfs(_m,current_x,current_y+1);

    // return cnt;
    
}

int main()
{
    int bx, by, hx, hy; //B点坐标 马坐标
    //int cnt;
    

    
    
    vector<Point> banned_points;

    cin >> bx >> by >> hx >> hy;

    // input test data
    //bx = 6;
    //by = 6;
    //hx = 3;
    //hy = 3;

    Point B = {bx, by}; //B点
    Point H = {hx, hy}; //马

    M m = {bx, by}; //地图

    banned_points = get_banned_points(H);
    m = set_banned_points(m, banned_points);
    m.tostring();

    //cnt = dfs(m,0,0);
    dfs(m,0,0);

    cout << cnt;



    return 0;
}

输入 6 6 3 3

输出40

应该输出6