Given an m×nm \times nm×n matrix of distinct numbers, return the lucky number in the matrix.
A lucky number is an element of the matrix such that it is the smallest element in its row and largest in its column.
Constraints:
m=m =m= matrix.length
matrix.length
n=n =n= matrix[i].length
matrix[i].length
1≤n1 \leq n1≤n, m≤50m \leq 50 ...