#include<bits/stdc++.h>
#define FILE "read"
#define MAXN 10100
#define INF 1e9
using namespace std;
const int dx[5]={1,1,-1,-1};
const int dy[5]={1,-1,1,-1};
struct node{int y,next,v,w;}e[MAXN<<1];
int R,C,n,A,B,S,T,cnt,ans,flag,len(1),Link[MAXN],vis[MAXN],dis[MAXN],flow[MAXN],LN[MAXN],LE[MAXN],Id[105][105];
char ch[105][105];
queue<int>q;
inline int read(){
	int x=0,f=1;  char ch=getchar();
	while(ch>'9'||ch<'0')  {if(ch=='-')  f=-1;  ch=getchar();}
	while(ch>='0'&&ch<='9') {x=x*10+ch-'0';  ch=getchar();}
	return x*f;
}
void insert(int x,int y,int v,int w){
	e[++len].next=Link[x];Link[x]=len;e[len].y=y;e[len].v=v;e[len].w=w;
	e[++len].next=Link[y];Link[y]=len;e[len].y=x;e[len].v=0;e[len].w=-w;
}
bool spfa(){
	memset(vis,0,sizeof(vis));
	memset(dis,10,sizeof(dis));
	int oo=dis[0]; vis[S]=1; dis[S]=0; q.push(S); flow[S]=INF;
	while(!q.empty()){
		int x=q.front(); q.pop(); vis[x]=0;
		for(int i=Link[x];i;i=e[i].next)if(dis[x]+e[i].w<dis[e[i].y]&&e[i].v){
			dis[e[i].y]=dis[x]+e[i].w;  
			flow[e[i].y]=min(flow[x],e[i].v);
			LN[e[i].y]=x;  LE[e[i].y]=i;
			if(!vis[e[i].y]) q.push(e[i].y),vis[e[i].y]=1;
		}
	}
	if(dis[T]==oo) return 0;
	ans+=flow[T]*dis[T];
	for(int i=T;i!=S;i=LN[i]) e[LE[i]].v-=flow[T],e[LE[i]^1].v+=flow[T];
	return 1;
}
int main(){
	freopen(FILE".in","r",stdin);
	freopen(FILE".out","w",stdout);
	R=read(); C=read(); n=read(); A=read(); B=read(); S=++cnt; T=++cnt;
	for(int i=1;i<=R;++i) scanf("%s",ch[i]+1);
	for(int i=1;i<=R;++i)for(int j=1;j<=C;++j)Id[i][j]=++cnt;
	for(int i=1;i<=n;++i){
		int x=read(),y=read();
		insert(S,Id[x][y],1,0);
	}
	for(int i=1;i<=n;++i){
		int x=read(),y=read();
		insert(Id[x][y],T,1,0);
	}
	for(int i=1;i<=R;++i)for(int j=1;j<=C;++j)if(ch[i][j]=='.'){
		for(int k=0;k<4;++k){
			int x=i+A*dx[k],y=j+B*dy[k];
			if(x<=0||y<=0||x>R||y>C||ch[x][y]=='*') continue;
			insert(Id[i][j],Id[x][y],INF,1);
		}
		for(int k=0;k<4;++k){
			int x=i+B*dx[k],y=j+A*dy[k];
			if(x<=0||y<=0||x>R||y>C||ch[x][y]=='*') continue;
			insert(Id[i][j],Id[x][y],INF,1);
		}
	}
	while(spfa());
	for(int i=Link[T];i;i=e[i].next)if(!e[i].v)flag=1;
	if(flag) puts("-1");
	else printf("%d\n",ans);
	return 0;
}