﻿ ABC262 B - Triangle (Easier) - Atcoder

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Score : $200$ points

### Problem Statement

You are given a simple undirected graph with $N$ vertices and $M$ edges. The vertices are numbered $1, \dots, N$, and the $i$-th $(1 \leq i \leq M)$ edge connects Vertex $U_i$ and Vertex $V_i$.

Find the number of tuples of integers $a, b, c$ that satisfy all of the following conditions:

• $1 \leq a \lt b \lt c \leq N$
• There is an edge connecting Vertex $a$ and Vertex $b$.
• There is an edge connecting Vertex $b$ and Vertex $c$.
• There is an edge connecting Vertex $c$ and Vertex $a$.

### Constraints

• $3 \leq N \leq 100$
• $1 \leq M \leq \frac{N(N - 1)}{2}$
• $1 \leq U_i \lt V_i \leq N \, (1 \leq i \leq M)$
• $(U_i, V_i) \neq (U_j, V_j) \, (i \neq j)$
• All values in input are integers.

### Input

Input is given from Standard Input in the following format:

$N$ $M$
$U_1$ $V_1$
$\vdots$
$U_M$ $V_M$


### Sample Input 1

5 6
1 5
4 5
2 3
1 4
3 5
2 5


### Sample Output 1

2


$(a, b, c) = (1, 4, 5), (2, 3, 5)$ satisfy the conditions.

### Sample Input 2

3 1
1 2


### Sample Output 2

0


### Sample Input 3

7 10
1 7
5 7
2 5
3 6
4 7
1 5
2 4
1 3
1 6
2 7


### Sample Output 3

4