func_code_string: #include <bits/stdc++.h>   using namespace std;   using pii = pair<int, int>;   int m, n;   pii a[100001];   vector<int> adj[100001];   bool is_chosen[100001];   bool is_visited[100001];   int cnt = 0;   template <typename T>   inline T read() {     T x = 0;     T multiplier = 1;     char ch = getchar();     while (ch <  0  || ch >  9 ) {       if (ch ==  - ) {         multiplier = -1;       }       ch = getchar();     }     while (ch >=  0  && ch <=  9 ) {       x = (x << 3) + (x << 1) + (ch & 15);       ch = getchar();     }     return x * multiplier;   }   void dfs(int u, int prt) {     if (is_chosen[a[u].first] && is_chosen[a[u].second]) {       return;     }     if (is_visited[u]) {       return;     }     is_visited[u] = true;     bool x = is_chosen[a[u].first], y = is_chosen[a[u].second];     if (!x) {       is_chosen[a[u].first] = true;       is_chosen[a[u].second] = true;       for (auto v : adj[a[u].first]) {         if (v != prt) {           dfs(v, u);         }       }     }     if (!y) {       is_chosen[a[u].first] = true;       is_chosen[a[u].second] = true;       for (auto v : adj[a[u].second]) {         if (v != prt) {           dfs(v, u);         }       }     }     is_chosen[a[u].first] = true;     is_chosen[a[u].second] = true;   }   int main() {     n = read<int>(), m = read<int>();     for (int i = 1; i <= m; i++) {       a[i].first = read<int>();       a[i].second = read<int>();     }     sort(a + 1, a + m + 1);     for (int i = 1; i <= m; i++) {       adj[a[i].first].push_back(i);       adj[a[i].second].push_back(i);     }     for (int i = 1; i <= m; i++) {       if (!is_visited[i]) {         dfs(i, -1);       }     }     for (int i = 1; i <= m; i++) {       cnt += !is_visited[i];     }     printf( %d n , cnt);     return 0;   }   