#include <bits/stdc++.h>
using namespace std;

int main() {
	int n; cin >> n;
    vector <pair <int,int>> v(n);
    for(int i = 0; i < n; i++){
        int a;
        cin >> a;
        v[i] = {a,i};
    }
    int cnt = 0;
    sort(v.begin(),v.end());
    int maxi = v[0].second;
    int ans = 0;
    int k=0,ve1=0,ve2=0;
    for(int i = 1; i < n; i++){
        
        if(v[i].second > maxi){
            maxi = max(maxi,v[i].second);
            ve1 = v[i].second;
        }
        if(maxi - v[i].second > ans){
            ans = maxi - v[i].second;
            k = v[i].second;
            ve2 = ve1;
        }
    }
    if(ve2 == 0){
        cout << -1;
        return 0;
    }
    cout << k+1 << ' ' << ve2+1;

}