Nested Segments

Description:

Input:

The first line contains one integer n (1 ≤ n ≤ 3·10⁵) — the number of segments.

Each of the next n lines contains two integers l_i and r_i (1 ≤ l_i ≤ r_i ≤ 10⁹) — the i-th segment.

Output:

Print two distinct indices i and j such that segment a_i lies within segment a_j. If there are multiple answers, print any of them. If no answer exists, print -1 -1.

Sample Input:

5
1 10
2 9
3 9
2 3
2 9

Sample Output:

2 1

Sample Input:

3
1 5
2 6
6 20

Sample Output:

-1 -1

Note:

In the first example the following pairs are considered correct:

• (2, 1), (3, 1), (4, 1), (5, 1) — not even touching borders;
• (3, 2), (4, 2), (3, 5), (4, 5) — touch one border;
• (5, 2), (2, 5) — match exactly.