Number of Good Pairs

In an undirected graph, count the unordered node pairs whose endpoints belong to different connected components.

This site's standard input/output format and supplementary bounds follow this problem's description.

输入格式

The input is N M (1≤N≤65,535, 0≤M≤2×10^5), followed by M lines of edges u v (1-based, 1≤u,v≤N). Duplicate edges and self-loops are allowed, and the result fits safely in a signed 32-bit integer.

输出格式

Output the good pair count (as a 64-bit integer).

样例 1

输入：

5 3
1 2
2 3
4 5

输出：

6

样例 2

输入：

4 0

输出：

6

样例 3

输入：

1 2
1 1
1 1

输出：

0