RT，只能输出 -1 -1

#include <iostream>
#include <cstdio>
#include <algorithm>

#define rint register int
#define endl '\n'

using std::cin;
using std::cout;

const int N = 1e5 + 5;
const int M = 1e6 + 5;
const int inf = 0x3f3f3f3f;

int idx, h[N], e[M], ne[M], w[M];
int d[N];
int maxx, minn;
int ans, res;
bool vis[N];
int n, m;

void add(int a, int b, int c)
{
    e[++idx] = b, w[idx] = c, ne[idx] = h[a], h[a] = idx;
}

void dfs(int x, int dist)
{
    if (d[x])
    {
        ans = std::__gcd(ans, abs(d[x] - dist));
        return;
    }
    d[x] = dist;
    vis[x] = 1;
    maxx = std::max(maxx, dist);
    minn = std::min(minn, dist);
    for (rint i = h[x]; i; i = ne[i])
    {
        int y = e[i];
        dfs(y, x + w[i]);
    }
}

int main()
{
    cin >> n >> m;

    for (rint i = 1; i <= m; i++)
    {
        int a, b;
        cin >> a >> b;
        add(a, b, 1);
        add(b, a, -1);
    }

    for (rint i = 1; i <= n; i++)
    {
        if (vis[i])
        {
            continue;
        }
        maxx = -inf;
        minn = inf;
        dfs(i, 1);
        res += maxx - minn + 1;
    }

    if (ans) // 找到环了
    {
        if (ans < 3)
        {
            cout << -1 << " " << -1 << endl;
            return 0;
        }
        for (rint i = 3; i <= ans; i++)
        {
            if (ans % i == 0)
            {
                cout << ans << " " << i << endl;
                return 0;
            }
        }
    }
    else //  没有环
    {
        if (res < 3)
        {
            cout << -1 << " " << -1 << endl;
            return 0;
        }
        cout << 3 << " " << res << endl;
    }

    return 0;
}