// UUID: 5d9148d0-fbc3-41a6-beb6-0229275f1ac5
#include <bits/stdc++.h>
using namespace std;

int main() {
	int n; cin >> n;
	vector<pair<int ,int>> nums(n);
	for (int i = 0; i < n; i++) {
		cin >> nums[i].first;
		nums[i].second = i + 1;
	}

	sort(nums.rbegin(), nums.rend());

	int minind = INT_MAX;
	int maxtav = 0;
	int ind;
	int a, b = 0;
	for (int i = 0; i < n; i++) {
		ind = nums[i].second;
		if (minind > ind) {
			minind = ind;
		}
		else {
			if (ind - minind > maxtav) {
				maxtav = ind - minind;
				a = minind;
				b = ind;
			}
		}
	}
	if (b == 0) {
		cout << -1;
	}
	else {
		cout << a << " " << b;
	}
}