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

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n; cin >> n;
    vector<int> v(n+1);
    for (int i = 0; i < n; i++) {
        int temp; cin >> temp;
        v[temp] = i + 1;
    }
    int diff = -1, maxEnd = -1;
    int maxDiff = -1;
    for (int i : v) {
        if (i == 0) continue;
        else if (i > maxEnd) {
            maxEnd = i;
        }
        else {
            int temp = maxEnd - i;
            if (diff < temp) {
                diff = temp;
                maxDiff = maxEnd;
            }
        }
    }
    if (maxDiff == -1) {
        cout << -1; return 0;
    }
    cout << maxDiff - diff << " " << maxDiff;
}

//5
//4 3 5 1 2

// 4 5 2 1 3