记录

#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define ve vector
#define endl '\n'
#define itn int
using namespace std;
class jf_set{
	private: 
		int *fa;
	public:
		jf_set(int size){
			fa=new int[size+1];
			for(int i=0;i<=size;i++)
				fa[i]=i;
		}
		jf_set(){
			fa=new int[10001];
			for(int i=0;i<=10001;i++)
				fa[i]=i;
		}
		void join(int a,int b){
			fa[find(a)]=find(b);
		}
		int find(int x){
			if(fa[x]!=x)fa[x]=find(fa[x]);
			return fa[x];
		}
		int same(int a,int b){
			return find(a)==find(b);
		}
};
jf_set a,b;
int main()
{
    ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
    //begin
    int n,p,m,q;
    cin>>n>>p>>m>>q;
    a=jf_set(n);
    b=jf_set(m);
    for(int i=0;i<p;i++){
    	int x,y;
    	cin>>x>>y;
    	a.join(x,y);
	}
	for(int i=0;i<q;i++){
		int x,y;
		cin>>x>>y;
		b.join(-x,-y);
	}
	int l1=a.find(1),l2=b.find(1);
	int me,wome;
	me=wome=0;
	for(int i=1;i<=n;i++)
		if(a.find(i)==l1)
			me++;
	for(int i=1;i<=m;i++)
		if(b.find(i)==l2)
			wome++;
	cout<<(me>wome?wome:me);
	//end
    return 0;
}