#include <iostream>
#include <vector>
#include <fstream>
using namespace std;
int a[100000];
int main()
{
    ifstream fin("a.txt");
    int n;
    cin >> n;
    vector<int>s;
    int maxim =-1;
    int maxim1 =-1;
    int maxim2 =-1;
    for(int i  =0; i < n; i++)
    {
        int a;
        cin >> a;
        int relativi =-1;
        for(int i =0; i <  s.size(); i++)
        {
            if(s[i]>a)
            {
                relativi=i;
                break;
            }
        }
        //cout << i << " " << relativi << endl;
        int lokaltav = i-relativi;
        if((lokaltav > maxim && relativi!=-1) or (lokaltav==maxim && relativi!=-1 && relativi < maxim1))
        {
            maxim = lokaltav;
            maxim1 = relativi;
            maxim2= i;
        }
        s.push_back(a);
    }
    if(maxim!=-1)
    cout << maxim1+1 << " " << maxim2+1;
    else
        cout << -1;
    return 0;
}