Amy asks Mr. B problem E. Please help Mr. B to solve the following problem. There are n people, who don't know each other at the beginning. There are m turns. In each turn, 2 of them will make friends with each other. The friend relation is mutual and transitive. If A is a friend of B, then B is also a friend of A. For example, if A is a friend of B, B is a friend of C, then A and C are friends. At the beginning and after each turn, please calculate the number of ways to select fourpeople from, such that any two of these four are not friends.
Amy asks Mr. B problem E. Please help Mr. B to solve the following problem. There are n people, who don't know each other at the beginning. There are m turns. In each turn, 2 of them will make friends with each other. The friend relation is mutual and transitive. If A is a friend of B, then B is also a friend of A. For example, if A is a friend of B, B is a friend of C, then A and C are friends. At the beginning and after each turn, please calculate the number of ways to select four people from, such that any two of these four are not friends.
（图片来源网络，侵删）
