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

int main()
{
    ll n, m; cin >> n >> m;
    vector<ll> freq(n+1, 0);
    for (int i = 0; i < m; i++){
        int eleje, vege; cin >> eleje >> vege;
        freq[eleje-1]++; freq[vege]--;
    }
    freq[0] = freq[0];
    for (int i = 1; i <= n; i++){
        freq[i] = freq[i] + freq[i-1];
    }
    ll ans1 = -1;
    ll maxs = 0;
    ll cnt = 0;
    for (int i = 0; i < n; i++){
        if (freq[i] == 0) cnt++;
        else cnt = 0;
        if (cnt > maxs){
            maxs = cnt;
            ans1 = i-cnt+1;
        }
    }
    if (maxs == 0) cout << -1;
    else cout << maxs << " " << ans1+1;
    return 0;
}