using System; using System.Collections; using System.Collections.Generic; using System.Collections.Specialized; using System.Text; using System.Text.RegularExpressions; using System.Linq; using System.IO; class Program { static void Main(string[] args) { new Magatro().Solve(); } } public class Scanner { private StreamReader Sr; private string[] S; private int Index; private const char Separator = ' '; public Scanner(Stream source) { Index = 0; S = new string[0]; Sr = new StreamReader(source); } private string[] Line() { return Sr.ReadLine().Split(Separator); } public string Next() { string result; if (Index >= S.Length) { S = Line(); Index = 0; } result = S[Index]; Index++; return result; } public int NextInt() { return int.Parse(Next()); } public double NextDouble() { return double.Parse(Next()); } public long NextLong() { return long.Parse(Next()); } public decimal NextDecimal() { return decimal.Parse(Next()); } public string[] StringArray(int index = 0) { Next(); Index = S.Length; return S.Skip(index).ToArray(); } public int[] IntArray(int index = 0) { return StringArray(index).Select(int.Parse).ToArray(); } public long[] LongArray(int index = 0) { return StringArray(index).Select(long.Parse).ToArray(); } public bool EndOfStream { get { return Sr.EndOfStream; } } } public class Magatro { private Scanner Cin; private int N, M; private int[] a, b; private List[] L; private void Scan() { Cin = new Scanner(Console.OpenStandardInput()); N = Cin.NextInt(); M = Cin.NextInt(); a = new int[M]; b = new int[M]; for (int i = 0; i < M; i++) { a[i] = Cin.NextInt(); b[i] = Cin.NextInt(); } } public void Solve() { Scan(); L = new List[N]; for (int i = 0; i < N; i++) { L[i] = new List(); } for (int i = 0; i < M; i++) { L[a[i]].Add(b[i]); L[b[i]].Add(a[i]); } int counter = 0; for (int i = 0; i < N - 3; i++) { for (int j = i + 1; j < N - 2; j++) { for (int k = j + 1; k < N - 1; k++) { for (int l = k + 1; l < N; l++) { if (IsShikaku(i, j, k, l)) { //Console.WriteLine($"{i} {j} {k} {l}"); counter++; } } } } } Console.WriteLine(counter); } private bool IsShikaku(int a, int b, int c, int d) { bool bb, cc, dd; bb = L[a].Contains(b); cc = L[a].Contains(c); dd = L[a].Contains(d); if (IsSankaku(a, b, c)) return false; if (IsSankaku(a, b, d)) return false; if (IsSankaku(a, c, d)) return false; if (IsSankaku(b, c, d)) return false; //Console.WriteLine($"{a} {b}{bb} {c}{cc} {d}{dd}"); if (bb) { if (cc) { if (!L[b].Contains(c)) { if (L[d].Contains(b) && L[d].Contains(c)) return true; } } if (dd) { if (!L[b].Contains(d)) { if (L[c].Contains(b) && L[c].Contains(d)) return true; } } } if (cc) { if (dd) { if (!L[c].Contains(d)) { if (L[b].Contains(c) && L[b].Contains(d)) return true; } } } return false; } private bool IsSankaku(int a,int b,int c) { if (L[a].Contains(b)) { if (L[a].Contains(c)) { if (L[b].Contains(c)) return true; } } return false; } }