#P1907. HowManyTriangles?

HowManyTriangles?

Q and T don't play games anymore. Now they study properties of all sorts of graphs together. 
Q invented  the  following  task :  she  takes  a  complete  undirected  graph  with n vertices , 
 chooses  some  m  edges  and  keeps  them . T  gets  the  n*(n-1)/2-m  remaining  edges .
Q and T are fond of "triangles" in graphs, that is, cycles of length 3. 
That's why they wonder: what total number of triangles is there in the two graphs formed by 
Q and  T's  edges ,  correspondingly?

Input

The first line contains two space-separated integers n and m (1 ≤ n ≤ 10^6, 0 ≤ m ≤ 10^6) — the number of vertices in the initial complete graph and the number of edges in Q's graph, correspondingly. Then m lines follow: the i-th line contains two space-separated integers ai, bi (1 ≤ ai, bi ≤ n, ai ≠ bi), — the numbers of the two vertices connected by the i-th edge in Q's graph. It is guaranteed that Q's graph contains no multiple edges and self-loops. It is guaranteed that the initial complete graph also contains no multiple edges and self-loops.

Consider the graph vertices to be indexed in some way from 1 to n.

Output

Print a single number — the total number of cycles of length 3 in Q and T's graphs together.

Sample Input

5 3
1 2
2 3
1 3

Sample Output

4

HINT

Source