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

using namespace std;

struct adat
{
    int szam, poz;
};

int i, n, mini, a, b;

bool comp(adat a, adat b)
{
    return a.szam>b.szam;
}

int main()
{
    cin>>n;

    vector <adat> x(n+1);

    for (i=1; i<=n; ++i)
    {
        cin>>x[i].szam;
        x[i].poz=i;
    }

    sort(x.begin()+1, x.end(), comp);

    mini=x[1].poz;
    for (i=2; i<=n; ++i)
    {
        if (x[i].poz<mini) mini=x[i].poz;
        else if(x[i].poz-mini>b-a)
        {
            b=x[i].poz;
            a=mini;
        }
    }

    if (b-a==0) cout<<-1;
    else cout<<a<<" "<<b;

    return 0;
}