#include<bits/stdc++.h>
#define int long long
using namespace std;
inline int read()
{
	int f=1,num=0;
	char c=getchar();
	while(c<'0'||c>'9'){if(c=='-') f=-1;c=getchar();}
	while(c>='0'&&c<='9') num=num*10+c-'0',c=getchar();
	return num*f;
}
const int N=200010,M=300010;
struct bian
{
	int x,y,z,bi;
}bs[2*M];
int n1,n2,m1,m2;
bool cmp(bian a,bian b){return a.z<b.z;}
int ans;
int fa[3][N],sz[3][N],l1,l2;
int get(int x,int xb)
{
	if(fa[xb][x]==x) return x;
	return fa[xb][x]=get(fa[xb][x],xb);
}
void merge(int x,int y,int xb)
{
	if(xb==1) l1--;else l2--;
	x=get(x,xb);y=get(y,xb);
	if(sz[xb][x]>sz[xb][y]) swap(x,y);
	fa[xb][x]=y;sz[xb][y]+=sz[xb][x];
	return;
}
signed main()
{
	freopen("emptyfist.in","r",stdin);
	freopen("emptyfist.out","w",stdout);
	n1=read();n2=read();m1=read();m2=read();
	for(int i=1;i<=n1;i++) fa[1][i]=i,sz[1][i]=1;for(int i=1;i<=n2;i++) fa[2][i]=i,sz[2][i]=1;l1=n1,l2=n2;
	for(int i=1;i<=m1+m2;i++) bs[i].x=read(),bs[i].y=read(),bs[i].z=read(),bs[i].bi=i;
	sort(bs+1,bs+1+m1+m2,cmp);
	for(int i=1;i<=m1+m2;i++)
	{
		if((bs[i].bi<=m1&&get(bs[i].x,1)==get(bs[i].y,1))||(bs[i].bi>m1&&get(bs[i].x,2)==get(bs[i].y,2))) continue;
		if(bs[i].bi<=m1) ans+=bs[i].z*l2,merge(bs[i].x,bs[i].y,1);
		else ans+=bs[i].z*l1,merge(bs[i].x,bs[i].y,2);
	}
	printf("%lld",ans);
	return 0;
}