#include <iostream>
#include <bits/stdc++.h>
using namespace std;

int main()
{
    long long n, m; cin >> n >> m;
    vector<int> apa(n+1);
    for (int i = 1; i <= m; i++){
        int a, b; cin >> a >> b;
        apa[b] = a;
    }
    vector<int> gy(n+1);
    int maxu = 0, ind = 0;
    for (int i = 1; i <= n; i++){
        gy[apa[apa[i]]]++;
    }
    for (int i = 1; i <= n; i++){
        if (gy[i] > maxu){
            maxu = gy[i]; ind = i;
        }
    }
    if (maxu == 0) cout << -1;
    else cout << ind << " " << maxu;
    return 0;
}