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>
char B[1 << 26], *S = B, C;
int X;
inline int read() {
  while ((C = *S++) < '0' || C > '9')
    ;
  for (X = C - '0'; (C = *S++) >= '0' && C <= '9';)
    X = (X << 3) + (X << 1) + C - '0';
  return X;
}
int f[1000000 + 5], r[1000000 + 5];
int gf(int k) { return f[k] ? f[k] = gf(f[k]) : k; }
int main() {
  fread(B, 1, 1 << 26, stdin);
  int n, m, x, y, i, cnt = 1;
  n = read();
  m = read();
  while (m--) {
    ++r[x = read()];
    ++r[y = read()];
    if (gf(x) != gf(y)) ++cnt, f[gf(x)] = gf(y);
  }
  if (cnt < n) return 0 * puts("0");
  for (i = 1, cnt = 0; i <= n; ++i)
    if (r[i] & 1) ++cnt;
  if (cnt & 1)
    cnt = 0;
  else if (!cnt)
    cnt = n;
  printf("%I64d", 1LL * cnt * (cnt - 1) >> 1);
}
