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


int main() {
    int n, m;
    cin >> n >> m;
    vector<int> T(n+2);
    T[n+1] = 1;
    for (int i = 0; i < m; i++) {
        int x, y;
        cin >> x >> y;
        T[x]++;
        T[y+1]--;
    }

    int cnt = 0, mx = 0, temp = 1;
    int ans;

    for(int i = 1; i <= n+1; i++) {
        T[i]+=T[i-1];
        if(T[i] == 0) {
            cnt++;
        } else {
            if (cnt > mx) {
                mx = cnt;
                ans = temp;
            }
            temp = i+1;
            cnt = 0;
        }
    }
    if (mx == 0) {
        cout << -1 << endl;
        return 0;
    }
    cout << mx << " " << ans << endl;
    return 0;
}