POJ 2524

#include<stdio.h>
#define M 50005
int ji[M];
int findme(int a)
{
while(ji[a]!=a)
{
a=ji[a];
}
return a;
}
void link(int a,int b)
{
int tmp;
tmp=b;
a=findme(a);
b=findme(b);
ji[b]=a;
while(ji[tmp]!=tmp)
{
tmp=ji[tmp];
ji[tmp]=a;
}
}
int main()
{
int m,a,b,n,i,rel,ca;
ca=0;
scanf("%d%d",&n,&m);
while(n!=0)
{
ca++;
for(i=1;i<=n;i++)
{
ji[i]=i;
}
rel=0;
while(m--)
{
scanf("%d%d",&a,&b);
link(a,b);
}
for(i=1;i<=n;i++)
{
rel+=(ji[i]==i);
}
printf("Case %d: %d\n",ca,rel);
scanf("%d%d",&n,&m);
}
return 0;
}