#include<bits/stdc++.h>
using namespace std;
constexpr int N=5005;
int n,m,l;
typedef long long ll;
constexpr ll inf=1e9,Inf=1e13;
constexpr int maxn=5005,maxm=1e5+5;
int s,t,tot=1,fir[maxn],to[maxm],nxt[maxm];ll val[maxm];
inline void addedge(int u,int v,ll w){++tot,nxt[tot]=fir[u],fir[u]=tot,to[tot]=v,val[tot]=w;}
inline void add(int u,int v,ll w){addedge(u,v,w),addedge(v,u,0);}
int dep[maxn],firr[maxn];
inline bool bfs(){
    memcpy(firr,fir,sizeof fir);
    memset(dep,0,sizeof dep);dep[s]=1;
    queue<int> q;q.push(s);
    while(!q.empty()){
        int p=q.front();q.pop();
        if(p==t) return 1;
        for(int i=fir[p];i;i=nxt[i])if(!dep[to[i]]&&val[i]) dep[to[i]]=dep[p]+1,q.push(to[i]);
    }
    return 0;
}
ll dfs(int p,ll res){
    if(p==t) return res;
    ll fl=0;
    for(int &i=firr[p];i;i=nxt[i])if(dep[to[i]]==dep[p]+1&&val[i]){
        ll z=dfs(to[i],min(res,val[i]));
        res-=z,fl+=z,val[i]-=z,val[i^1]+=z;
    }
    if(!fl) dep[p]=0;
    return fl;
}
int main(){
    cin>>n>>m>>l;
    vector<int> v;v.push_back(0);
    for(int i=1;i<=l*n;i++){
        string s;cin>>s;
        for(char c:s) v.emplace_back(c=='W');
    }
    s=0,t=n*m*l+1;
    ll ans=-inf*n*m*l;
    for(int i=0;i<l*n;i++){
        for(int j=1;j<=m;j++){
            int x=i*m+j,y;cin>>y;
            add(s,x,x==n*m*l?Inf:inf+(v[x]?y:0));
            add(x,t,x==1?Inf:inf+(v[x]?0:y));
            if(j<m) add(x,x+1,Inf);
            if(i%n!=n-1) add(x,x+m,Inf);
            if(i/n!=l-1) add(x,x+n*m,Inf);
        }
    }
    while(bfs()) ans+=dfs(s,1e18);
    cout<<ans<<'\n';
    return 0;
}