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

using namespace std;



int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	vector<pair<int, int>> v;
	int n, t;
	cin >> n;
	for (int i = 1; i <= n; ++i)
	{
		cin >> t;
		v.push_back({ t, i });
	}
	sort(v.begin(), v.end());
	int maxi = 0, res = -1, ind = -1;
	for (auto& e : v)
	{
		if (e.second > maxi)
			maxi = e.second;
		if (maxi - e.second > res)
		{
			res = maxi - e.second;
			ind = maxi;
		}
	}
	if (res == -1)
	{
		cout << -1;
		return 0;
	}
	cout << ind - res << " " << ind;
}