func_code_string: #include <bits/stdc++.h>   using namespace std;   template <typename T, typename U>   inline void smin(T &a, U b) {     if (a > b) a = b;   }   template <typename T, typename U>   inline void smax(T &a, U b) {     if (a < b) a = b;   }   template <class T>   inline void gn(T &first) {     char c, sg = 0;     while (c = getchar(), (c >  9  || c <  0 ) && c !=  - )       ;     for ((c ==  -  ? sg = 1, c = getchar() : 0), first = 0; c >=  0  && c <=  9 ;          c = getchar())       first = (first << 1) + (first << 3) + c -  0 ;     if (sg) first = -first;   }   template <class T, class T1>   inline void gn(T &first, T1 &second) {     gn(first);     gn(second);   }   template <class T, class T1, class T2>   inline void gn(T &first, T1 &second, T2 &z) {     gn(first);     gn(second);     gn(z);   }   template <class T>   inline void print(T first) {     if (first < 0) {       putchar( - );       return print(-first);     }     if (first < 10) {       putchar( 0  + first);       return;     }     print(first / 10);     putchar(first % 10 +  0 );   }   template <class T>   inline void printsp(T first) {     print(first);     putchar(   );   }   template <class T>   inline void println(T first) {     print(first);     putchar(  n );   }   template <class T, class U>   inline void print(T first, U second) {     printsp(first);     println(second);   }   template <class T, class U, class V>   inline void print(T first, U second, V z) {     printsp(first);     printsp(second);     println(z);   }   int power(int a, int b, int m, int ans = 1) {     for (; b; b >>= 1, a = 1LL * a * a % m)       if (b & 1) ans = 1LL * ans * a % m;     return ans;   }   int root[1111111], deg[1111111], edge[1111111];   int find_root(int u) {     if (u == root[u]) return u;     return root[u] = find_root(root[u]);   }   int main() {     int n, m, u, v;     int self = 0;     gn(n, m);     for (int i = 1; i <= n; i++) root[i] = i;     for (int i = 0; i < m; i++) {       gn(u, v);       if (u == v)         self++;       else         deg[u]++, deg[v]++;       u = find_root(u);       v = find_root(v);       if (u == v)         edge[u]++;       else {         root[v] = u;         edge[u] += (edge[v] + 1);       }     }     int yes = 0, cnt = 0;     for (int i = 1; i <= n; i++)       if (edge[i] == m) {         yes = 1;         break;       }     if (!yes) return puts( 0 );     long long ans = 0;     for (int i = 1; i <= n; i++) ans += (long long)deg[i] * (deg[i] - 1) / 2;     ans += (long long)self * (m - self) + (long long)self * (self - 1) / 2;     println(ans);   }   