#include <iostream>
#include <algorithm>
#include <fstream>
#define ff for(i=0; i<n; i++)
using namespace std;
struct kecske
{
    int a, s;
};
bool f(kecske a, kecske b)
{
    if(a.a!=b.a)return a.a < b.a;
    else return a.s < b.s;
}
int main()
{
    int n, i, mi=-1, ma=0, c=-1, d=-1;
    cin >> n;
    kecske t[n];
    ff{
        cin >> t[i].a;
        t[i].s = i;
    }
    sort(t, t+n, f);
    ff{
        if(t[i].s > mi)mi=t[i].s;
        if(mi > t[i].s && mi-t[i].s > ma)
        {
            c = mi+1;
            d = t[i].s+1;
            ma = mi-t[i].s;
        }

    }
    if(d==-1)cout<<-1;
    else cout << d << " " << c;
    return 0;
}