#include <bits/stdc++.h>
using namespace std;

int main() {
	int n;
	cin >> n;
	vector<int> v(n);
	for (int i = 0; i < n; i++) cin >> v[i];
	int mx = -100001, ind = -1, len = 0;
	vector<int> vmx;
	for (int i = 0; i < n; i++)
	{
		if (v[i] > mx)
		{
			mx = v[i];
			vmx.push_back(i);
			continue;
		}
		else
		{
			for (int j = 0; j < vmx.size(); j++)
			{
				if (i - vmx[j] <= len)
				{
					break;
				}
				if (v[i] < v[vmx[j]])
				{
					ind = vmx[j];
					len = i-vmx[j];
				}
			}
		}
	}
	if (ind == -1) cout << ind;
	else cout << ind+1 << " " << ind+len+1;
}