/*
4 3 5 1 2




4 5 2 1 3

*/


#include <bits/stdc++.h>

using namespace std;

int main(){

    ios_base::sync_with_stdio(0); cin.tie(0);

    int n; cin >> n;
    vector<int> v(n+1);

    for (int i = 0; i < n; i++){
        int a; cin >> a;
        v[a] = i+1;
    }

    int mx = 0, tav = 0, i = 0, j = 0;

    for (int x : v){

        mx = max(mx, x);

        if (mx - x > tav){
            i = mx; j = x; tav = mx-x;
        }

    }

    if (tav == 0){
        cout << -1; return 0;
    }

    cout << j << " " << i;


    return 0;
}