Input:
N = 3
M[][] = {{0 1 0},
{0 0 0},
{0 1 0}}
Output: 1
Explanation: 0th and 2nd person both
know 1. Therefore, 1 is the celebrity.
Input:
N = 2
M[][] = {{0 1},
{1 0}}
Output: -1
Explanation: The two people at the party both
know each other. None of them is a celebrity.