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

int main() {
	int n;
	cin >> n;
	vector<int> szam(n);
	vector<int> mini(n, 100001);
	cin >> szam[0];
	for (int i = 1; i < n; i++) {
		cin >> szam[i];
	}
	mini[n - 1] = szam[n - 1];
	for (int i = n - 2; i >= 0; i--) {
		mini[i] = min(szam[i], mini[i + 1]);
	}
	int maxi = 0;
	pair<int, int> maxii;
	for (int i = 0; i < n; i++) {
		int lo = i, hi = n - 1;
		while (lo < hi) {
			int mid = lo + (hi - lo + 1) / 2;
			if (mini[mid] >= szam[i]) hi = mid - 1;
			else lo = mid;
		}
		if (lo - i > maxi && szam[i] > szam[lo]) {
			maxi = lo - i;
			maxii.first = i + 1;
			maxii.second = lo + 1;
		}
	}
	if (maxi != 0) cout << maxii.first << " " << maxii.second;
	else cout << -1;
}