#include <iostream>

using namespace std;

int main()
{
    int n;
    cin >> n;
    int t[n];
    for(int i=0; i<n; i++){
        cin >> t[i];
    }
    int max_inv = 0;
    int max_i = 0, max_j = 0;
    for(int j=n-1; j>0; j--){
        for(int i=0; i<j; i++){
            if(t[i] > t[j]){
                if(j-i > max_inv){
                    max_inv = j-i;
                    max_i = i+1;
                    max_j = j+1;
                }
            }
        }
    }
    if(max_i == 0 && max_j == 0){
        cout << -1;
    }
    else{
        cout << max_i << " " << max_j;
    }
}