1272. Non-Yekaterinburg Subway

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<vector>

using namespace std;
const int INF=0x3f3f3f3f;
const int N=10005;
int f
;
int findx(int x)
{
if(f[x]!=x)
f[x]=findx(f[x]);
return f[x];
}
int main()
{
int n,k,m;
while(scanf("%d %d %d",&n,&k,&m)!=EOF)
{
for(int i=1;i<=n;++i)
f[i]=i;
while(k--)
{
int l,r;
scanf("%d %d",&l,&r);
f[findx(l)]=findx(r);
}
int ans=0;
while(m--)
{
int l,r;
scanf("%d %d",&l,&r);
if(findx(l)!=findx(r))
{++ans;f[findx(l)]=r;}
}
printf("%d\n",ans);
}
return 0;
}