// inverzio.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
#include <deque>
#include <algorithm>

using namespace std;
struct adat
{
    long long ertek, hely;
};

int n, i, j, maxi,kezd,veg;
deque<adat>x;
bool comp(adat a, adat b)
{
    return a.ertek > b.ertek;
}

int main()
{
    cin >> n;
    x.resize(n + 1);
    for (i = 1; i <= n; ++i)
    {
        cin >> x[i].ertek;
        x[i].hely = i;
    }
    sort(x.begin()+1, x.end(), comp);
    maxi = x[1].hely;
    for (i = 2; i <= n; ++i)
    {
        if (x[i].hely < maxi) maxi = x[i].hely;
        else if (x[i].hely - maxi > veg - kezd);
        {
            veg = x[i].hely;
            kezd = maxi;
        }
    }
    if (veg - kezd == 0) cout << -1;
    else cout << kezd << " " << veg;
    return 0;
}
/*
5
4 3 5 1 2

*/
// Run program: Ctrl + F5 or Debug > Start Without Debugging menu
// Debug program: F5 or Debug > Start Debugging menu

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