题目：

代码： 

#include<iostream>
using namespace std;
const int N=50010;
int p[N],d[N];
int n,m;int find(int x){if(p[x]!=x){    int u=find(p[x]);d[x] += d[p[x]];p[x]=u;}return p[x];
}int main(){scanf("%d%d",&n,&m);for(int i=1;i<=n;i++) p[i]=i;int res=0;while(m--){int t,x,y;scanf("%d%d%d",&t,&x,&y);if(x>n || y>n) res++;else{int px=find(x),py=find(y);if(t==1){if(px==py && (d[x]-d[y]) % 3) res++;else if(px!=py){p[px]=py;d[px]=d[y]-d[x];}}else{if(px==py && (d[x]-d[y]-1)%3) res++;else if(px!=py){p[px]=py;d[px]=d[y]+1-d[x];}}}}printf("%d",res);
}