#include <iostream>
#include <vector>

using namespace std;

int main()
{
	int n;
	cin >> n;
	vector<int> v(n);
	for(int i = 0; i < n; i++)
    {
        int x;
        cin >> x;
        v[x - 1] = i;
    }
    int x = v[0];

    int begs = -1;
    int ends = -1;
    for(int i = 1; i < n; i++)
    {
        if(x < v[i])
        {
            x = v[i];
        }
        else
        {
            if(x - v[i] > ends - begs)
            {
                begs = v[i];
                ends = x;
            }
        }
    }
    if(begs == -1)
    {
        cout << -1;
    }
    else
    {
        cout << begs + 1 << " " << ends + 1;
    }
	return 0;
}