#include <bits/stdc++.h>

using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<int> a(n);

    for(int i =1; i<n+1; i++){
        int k;
        cin >> k;
        a[k]=i;
    }
    int m = -1;
    int l = 0;
    pair<int, int> solve;
    for(int i =0; i<n; i++){
        if (m-a[i]>l){
            l = m-a[i];
            solve.first=a[i];
            solve.second=m;
        }if (m<a[i]){
            m = a[i];
        }
    }
    if (l==0){
        cout << -1;
    }else{
        cout << solve.first << " " <<  solve.second;
    }
    return 0;
}