#include<iostream>

#include<cstdio>

#include<cstring>

#include<queue>

using namespace std;

#define N 200005

inline int Min(int a,int b){return a<b?a:b;}

inline int Abs(int a){return a<?-a:a;}

const int inf=1e8;

char a[][];

int R,C,D,S,T,d[N],cur[N],tot; bool vis[N];

int cnt=,hd[N],nxt[N],ed[N],poi[N],val[N];

queue <int> h;

inline void adde(int x,int y,int v){

    nxt[ed[x]]=++cnt, hd[x]=hd[x]?hd[x]:cnt,

    ed[x]=cnt, poi[cnt]=y, val[cnt]=v;

}

inline void link(int x,int y,int v){adde(x,y,v),adde(y,x,);}

inline int id(int x,int y){return (x-)*C+y;}

bool Bfs(){

    memset(vis,,sizeof(vis));

    h.push(S); vis[S]=;

    while(!h.empty()){

        int x=h.front(); h.pop();

        for(int i=hd[x];i;i=nxt[i]){

            int to=poi[i];

            if(!vis[to]&&val[i]>)

                vis[to]=,d[to]=d[x]+,h.push(to);

        }

    }return vis[T];

}

int Dfs(int x,int a){

    if(x==T||a==) return a;

    int F=,f;

    for(int &i=cur[x];i&&a;i=nxt[i]){

        int to=poi[i];

        if(d[to]==d[x]+&&(f=(Dfs(to,Min(a,val[i]))))>)

            F+=f,a-=f,val[i]-=f,val[i^]+=f;

    }return F;

}

int dinic(){

    int re=;

    while(Bfs()){

        for(int i=;i<=T;++i) cur[i]=hd[i];

        re+=Dfs(S,inf);

    }return re;

}

void draw(int x,int y){//向周围距离<=d的点连边

    if(a[x][y]=='') return ;

    int p=id(x,y); bool tt=;

    link(p<<,p<<|,a[x][y]-'');

    for(int i=x-D;i<=x+D;++i)

        for(int j=y-D;j<=y+D;++j){

            if((i==x&&j==y)||Abs(x-i)+Abs(y-j)>D) continue;

            if(i>&&i<=R&&j>&&j<=C) link(p<<|,id(i,j)<<,inf);

            else if(tt) link(p<<|,T,inf),tt=;

        }

}

int main(){

    scanf("%d%d%d",&R,&C,&D);

    S=R*C*+; T=S+;

    for(int i=;i<=R;++i) scanf("%s",a[i]+);

    for(int i=;i<=R;++i)

        for(int j=;j<=C;++j)

            draw(i,j);

    for(int i=;i<=R;++i) scanf("%s",a[i]+);

    for(int i=;i<=R;++i)

        for(int j=;j<=C;++j)

            if(a[i][j]=='L')

                link(S,id(i,j)<<,),++tot;

    printf("%d",tot-dinic());

    return ;

}