#include <iostream>
#include <vector>

using namespace std;

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

    vector<int> s(n+1);
    for (int i = 0; i < n; i++)
    {
        cin >> s[i];
    }

    vector<int> rs(n+1);
    for (int i = 0; i < n; i++)
    {
        rs[s[i]] = i+1;
    }

    int maxs = -1;
    int maxi = 0;
    int maxj = 0;
    int legnagyobb = rs[1];
    for (int i = 2; i < n+1; i++)
    {
        if (rs[i] < legnagyobb)
        {
            if (maxs < legnagyobb - rs[i])
            {
                maxs = legnagyobb - rs[i];
                maxi = rs[i];
                maxj = legnagyobb;
            }

        }
        else
        {
            legnagyobb = rs[i];
        }

    }
    if (maxs != -1)
    {
        cout << maxi << " " << maxj;
    }
    else
    {
        cout << maxs;
    }

}