#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int n,k,maxi1,maxi2,elso,vegso;

vector<pair<int, int>> v;

int main()
{
	cin >> n;
	for (int i = 1; i <= n; ++i)
	{
		cin >> k;
		v.push_back({ k,i });
	}
	sort(v.begin(), v.end());
	for (auto& l : v)
	{
		if (l.second > maxi1)
		{
			maxi1 = l.second;
		}
		else if(maxi1-l.second>maxi2)
		{
			maxi2 = maxi1 - l.second;
			elso = l.second;
			vegso = maxi1;
		}
	}
	if (maxi2 == 0)
		cout << -1;
	else
	cout << elso << " " << vegso;
	

}