#include <iostream>
#include <algorithm>

using namespace std;

struct s{
    int szam, ind;
};

bool alma(s x1, s x2){
    return x1.szam<x2.szam;
}

int main()
{
    int n;
    cin >> n;
    s a[n];
    for(int i=0; i<n; i++){
        cin >> a[i].szam;
        a[i].ind=i;
    }
    int maxd=0, maxind=-1, m1=-1, m2=-1;
    sort(a, a+n, alma);
    for(int i=0; i<n; i++){
        /*while(i!=n-1&&a[i].szam==a[i+1].szam){
            i++;
        }*/
        //cout << "szam: " << a[i].szam << "\nind:" << a[i].ind << "\nmaxind: " << maxind << "\n\n";
        if(maxind>a[i].ind&&maxd<=maxind-a[i].ind){
            maxd=maxind-a[i].ind;
            m1=a[i].ind+1;
            m2=maxind+1;
            //cout << m1 << ' ' << m2<< "\nmaxd: " << maxd << "\n\n";
        }
        if(a[i].ind>maxind){
            maxind=a[i].ind;
        }
    }
    if(m1!=-1) cout << m1 << ' ' << m2 << '\n';
    else cout << -1 << '\n';
    return 0;
}