1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
#include <map>

using namespace std;

int vis[10000];

vector<int> v[10000];
map<pair<int, int>, int> S;

void dfs(int u)
{
  vis[u] = 1;
  
  for (int i = 0; i < v[u].size(); i++)
  {
    int v1 = v[u][i];
    auto it = S.find({u, v1});
    if (!vis[v1] && it->second)
    {
      dfs(v1);
    }
  }
}

int main()
{
  int n, m;
  scanf("%d %d", &n, &m);
  
  vector<pair<int, int>> edges;
  for (int i = 0; i < m; i++)
  {
    int x, y;
    scanf("%d %d", &x, &y);
    --x, --y;
    auto it = S.find({x, y});
    auto it2 = S.find({y, x});
    if (it == S.end())
    {
      v[x].push_back(y);
      v[y].push_back(x);
      S.insert(pair<pair<int, int>, int>({x, y}, 1));
      S.insert(pair<pair<int, int>, int>({y, x}, 1));
    }
    else
    {
      it->second++;
      it2->second++;
    }
    edges.push_back({x, y});
    edges.push_back({y, x});
  }
  
  int ret = 0;
  
  for (int i = 0; i < m; i++)
  {
    auto it = S.find(edges[2 * i]);
    auto it2 = S.find(edges[2 * i + 1]);
    it->second--;
    it2->second--;
    
    for (int j = i + 1; j < m; j++)
    {
      auto it = S.find(edges[2 * j]);
      auto it2 = S.find(edges[2 * j + 1]);
      it->second--;
      it2->second--;

      for (int k = j + 1; k < m; k++)
      {
        auto it = S.find(edges[2 * k]);
        auto it2 = S.find(edges[2 * k + 1]);
        it->second--;
        it2->second--;
        
        memset(vis, 0, 4 * n);
        int skl = 0;
        for (int l = 0; l < n; l++)
        {
          if (!vis[l])
          {
            dfs(l);
            skl++;
          }
        }
        if (skl > 1)
        {
          ret++;
        }
        it->second++;
        it2->second++;
      }
      it->second++;
      it2->second++;
    }
    it->second++;
    it2->second++;
  }
  
  printf("%d\n", ret);
  
  return 0;
}