cpp

#include<iostream>
#include<cmath>
using namespace std;
long long a[30][30] = { 0 };
long long f(int i, int j, int n, int m)
{
	
	if (j > m)return 0;
	if (i > n)return 0;
	if (a[i][j] > 0)
	{
		return a[i][j];
	}
	if (a[i][j] == -1)
	{
		return 0;
	}
	a[i][j] += f(i + 1, j, n, m) + f(i, j + 1, n, m);

}
int main()
{
	int n, m, x, y;
	cin >> n >> m >> x >> y;
	a[n][m] = 1;
	long long dx[] = { -2,-2,-1,1,2,2,1,-1 };
	long long dy[] = { -1,1,2,2,1,-1,-2,-2 };
	for (int i = 0; i < 8; i++)
	{
		if (x + dx[i] < 0)break;
		if (y + dy[i] < 0)break;
		a[x + dx[i]][y + dy[i]] = -1;
	}
	a[x][y] = -1;
	f(0, 0, n, m);
	if (a[0][0] < 0)
	{
		a[0][0] = 0;
	}
	cout << a[0][0];

}