#include <bits/stdc++.h>

using namespace std;

int main()
{
    int n,a; cin >> n;
    vector <int> v(n+1);
    for(int i = 1; i <= n; i++){
        cin >> a;
        v[a] = i;
    }
    int maxi = 0,mini = 0;
    int ans = 0;
    int l=0,r=0;
    for(int i = 1; i <= n; i++){
        maxi = max(maxi,v[i]);
        if(maxi-v[i] > ans){
            ans = maxi - v[i];
            l = maxi;
            r = v[i];
        }
    }
    if(ans == 0){
        cout << -1;
        exit(0);
    }
    cout << r << ' ' << l;
}