#include <iostream>
#include<vector>
#include <algorithm>
using namespace std;

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	int n;
	int maximum=-1,kezdo=0;
	cin >> n;
	vector<int> tomb(n);
	vector<int> seged(n);
	for (int i = 0; i < n; ++i) cin >> tomb[i];
	seged[n - 1] = tomb[n - 1];
	for (int i = n - 2; i >= 0; --i)
	{
		seged[i] = min(tomb[i], seged[i + 1]);
	}
	for (int i = 0; i < n; ++i)
	{
		auto it = lower_bound(seged.begin()+i+1, seged.end(), tomb[i]) - 1;
		int d = it - seged.begin() - i;
		if (d > maximum and d!=0)
		{
			maximum = d;
			kezdo = i + 1;
		}
	}
	if (maximum != -1) cout << kezdo << " " << kezdo + maximum;
	else cout << -1;
}