1 #include <iostream> 2 #include <cstring> 3 #include <cstdlib> 4 #include <cctype> 5 #include <cmath> 6 #include <string> 7 #include <cstdio> 8 #include <algorithm> 9 #include <numeric>10 using namespace std;11 12 const int maxnn = 1e4 + 10;13 int cnt = 0, father[maxnn];14 15 int getFather (int x) {16     if (father[x] != x) {17         father[x] = getFather (father[x]);18     }19     return father[x];20 }21 22 void Union (int p, int q) {23     int x = getFather (p);24     int y = getFather (q);25     if (x != y) {26         father[y] = x;27     } else {28         cnt ++;29     }30 }31 32 int main () {33     int n, x;34     while (cin >> n >> x) {35         for (int i = 0; i < x; ++ i) {36             father[i] = i;37         }38         cnt = 0;39         for (int i = 0 ;i < x; ++ i) {40             int p, q; scanf("%d%d", &p, &q);41             Union (p, q);42         }43 44 45         /*for (int i = 0; i < n; ++ i) {46             if (getFather (i) == i) {47                 ans ++;48             }49         }*/50         cout << cnt << endl;51     }52     return 0;53 }