There are N employees at Zluri. Some of them are friends, while some are not. Their friendship is transitive in nature. For example, if A is a direct friend of B, and B is a direct friend of C, then A is an indirect friend of C. And we defined a friend group, as a group of employees who are direct or indirect friends. Given a N*N matrix M representing the friend relationship between employees in the company. If M[i][j] = 1, then the ith and jth employees are direct friends with each other, otherwise not. And you have to output the total number of friend groups among all the employees. example : Input: [[1,1,0], [1,1,0], [0,0,1]] Output: 2