#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;

int main()
{
    int n;
    cin >> n;
    vector<int> indexek(n + 1, 0);
    for(int i = 0; i < n; i++){
        int a;
        cin >> a;
        indexek[a] = i + 1;
    }

    vector<int> dp(n + 1, 0);
    dp[1] = -1;
    bool vanVal = false;
    pii valasz = {0, 0};
    pii kovi = {1, indexek[1]};

    for(int i = 2; i <= n; i++){
        if(kovi.second > indexek[i]){
            dp[i] = kovi.second;
        } else{
            dp[i] = -1;
            kovi.second = indexek[i];
            kovi.first = i;
        }

        if(dp[i] != -1 && valasz.second - valasz.first < dp[i] - indexek[i]){
            valasz.first = indexek[i];
            valasz.second = dp[i];
            vanVal = 1;
        }
    }

    if(vanVal){
        cout << valasz.first << " " << valasz.second << "\n";
    } else{
        cout << "-1\n";
    }
}