100 10
87 73
15 71
14 33
1 4
20 80
65 67
36 36
25 4
22 21
7 97
 4 2
3 3
3 4
 5 4
3 3
4 4
5 5
1 2
 4 4
1 2
2 3
3 1
4 4
 4 3
1 1
2 3
3 4
 1000000 1
255765 255765
 4 3
1 2
2 3
4 4
 4 2
1 1
1 2
 3 3
1 1
2 2
3 3
 5 4
1 1
2 3
2 4
2 5
 4 5
1 4
3 4
1 2
2 3
2 4
 4 4
2 3
2 4
3 4
4 4
 10 9
8 10
3 10
2 8
9 3
4 8
1 10
7 9
5 4
7 3
 10 10
1 2
2 3
3 4
4 5
5 1
6 6
7 7
8 8
9 9
10 10
 5 5
1 4
3 4
1 2
2 3
2 4
 3 3
1 2
2 2
3 3
 5 3
1 1
2 2
3 3
 6 12
1 2
1 3
2 3
1 1
2 2
3 3
4 5
5 6
4 6
4 4
5 5
6 6
 4 4
1 2
2 3
1 3
4 4
 5 4
1 2
3 3
4 4
5 5
 7 13
6 7
2 7
3 7
4 3
5 2
1 4
7 7
3 1
5 5
3 3
1 5
2 6
6 6
 2 2
1 1
2 2
 5 5
1 1
2 2
3 3
4 4
5 5
 1 1
1 1
 7 3
1 1
3 3
6 6
 3 3
1 1
2 3
3 3

0 1 0 0 0 0 0 1 0 0 8 6 12 0 8 0 0 0 0 0 57 0 0 0 0 0
#include <bits/stdc++.h>
using namespace std;
const int N = 1e6;
int n, m;
vector<int> v[N];
int c = 0;
int cmp[N];
int sz[N];
void dfs(int i) {
  cmp[i] = c;
  sz[c]++;
  for (int j : v[i])
    if (cmp[j] == -1) dfs(j);
}
int main() {
  srand(time(NULL));
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    int x, y;
    cin >> x >> y;
    x--;
    y--;
    v[x].push_back(y);
    if (x != y) v[y].push_back(x);
  }
  fill(cmp, cmp + n, -1);
  fill(sz, sz + n, 0);
  for (int i = 0; i < n; i++) {
    if (cmp[i] == -1) {
      dfs(i);
      c++;
    }
  }
  int d = 0;
  for (int i = 0; i < n; i++)
    if (v[i].size() == 0) d++;
  for (int i = 0; i < n; i++)
    if (v[i].size() != 0 && sz[cmp[i]] != n - d) {
      cout << "0\n";
      return 0;
    }
  cout << (long long)(m) * (m - 1) / 2 << endl;
  return 0;
}
