#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

struct par
{
    int szam, index;
};

bool cmp (par a, par b)
{
    return (a.szam < b.szam);
}

int main()
{
    int n, be;
    cin >> n;

    vector <par> v;

    for (int i = 1; i <= n; i ++) {
        cin >> be;
        v.push_back(par{be, i});
    }

    sort(v.begin(), v.end(), cmp);

    int maxi = 0, dif = -1, kezd = -1, veg = -1;

    for (par x : v)
    {
        if (x.index > maxi)
        {
            maxi = x.index;
        }
        else if (maxi - x.index > dif)
        {
            dif = maxi - x.index;
            kezd = x.index;
            veg = maxi;
        }
    }

    if (dif == -1) cout << -1;
    else cout << kezd << ' ' << veg;

    return 0;
}