// inverzio.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

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

int main()
{
	int a, n; cin >> n;
	vector <int> poz(n + 1);
	for (int i = 1; i <= n; ++i) {
		cin >> a;
		poz[a] = i;
	}
	int kezd = 0, veg = 0;
	int akt;
	int maxitav;
	for (int i = 1; i <= n; ++i) {
		if (akt < poz[i]) {
			akt = poz[i];
		}
		else{
			if (maxitav < akt-poz[i]) {
				maxitav = akt- poz[i];
				kezd = poz[i]; veg = akt;
			}
		}
	}
	if (kezd == 0) cout << "-1";
	else cout << kezd << " " << veg;
}
/*
* 1 2 3 4 5
* 4 5 2 1 3
*/

// Run program: Ctrl + F5 or Debug > Start Without Debugging menu
// Debug program: F5 or Debug > Start Debugging menu

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