1 #include<iostream> 2 #include<cstdio> 3 #define MAXN 1111 4 int TestCase = 0; 5 int N,M; 6 int tr[MAXN]; 7 int tr_find(int x) 8 { 9     while(tr[x] != x)10         x = tr[x];11     return x;12 }13 void tr_merge(int a,int b)14 {15     int ra = tr_find(a);16     int rb = tr_find(b);17     if(ra!=rb)18         tr[ra] = rb;19     return;20 }21 int main()22 {23 //    freopen("in.txt","r",stdin);24     scanf("%d",&TestCase);25     while(TestCase --) {26         scanf("%d%d",&N,&M);27         for(int i = 1; i <= N; i++)28             tr[i] = i;29         while(M--) {30             int a,b;31             scanf("%d%d",&a,&b);32             tr_merge(a,b);33         }34         int s = 0;35         for(int i = 1; i <= N; i++)36 //            std::cout<<" "<<tr[i];37             if(tr[i] == i)38                 ++s;39         printf("%d\n",s);40     }41 }