1 #include "bits/stdc++.h"
2 #define fi first
3 #define se second
4 using namespace std;
5 const int MAX=1e5+5;
6 const int oo=1e9;
7 char s[35][35];
8 int n,m,c,a[35],ss,tt;
9 int tot,head[MAX],adj[MAX],wei[MAX],nxt[MAX];
10 int deep[MAX];
11 int dx[]={1,0,-1,0};
12 int dy[]={0,1,0,-1};
13 void addedge(int u,int v,int w){
14 tot++;
15 adj[tot]=v;
16 wei[tot]=w;
17 nxt[tot]=head[u];
18 head[u]=tot;
19 tot++;
20 adj[tot]=u;
21 wei[tot]=0;
22 nxt[tot]=head[v];
23 head[v]=tot;
24 }
25 inline int getid(int x,int y,int z){
26 if (x<1 || x>n || y<1 || y>m) return MAX-5;
27 return 2*((x-1)*m+y)+z;
28 }
29 bool bfs(){
30 int i,j,zt;
31 queue <int> q;
32 while (!q.empty()) q.pop();
33 q.push(ss);
34 memset(deep,-1,sizeof(deep));
35 deep[ss]=0;
36 while (!q.empty()){
37 zt=q.front(); q.pop();
38 for (i=head[zt];i;i=nxt[i])
39 if (deep[adj[i]]==-1 && wei[i]>0){
40 deep[adj[i]]=deep[zt]+1;
41 q.push(adj[i]);
42 }
43 }
44 return (deep[tt]!=-1);
45 }
46 int dfs(int x,int v){
47 if (x==tt) return v;
48 int i,j,now=0,zt;
49 for (i=head[x];i && now<v;i=nxt[i])
50 if (deep[adj[i]]==deep[x]+1 && wei[i]>0){
51 zt=dfs(adj[i],min(wei[i],v-now));
52 now+=zt;
53 wei[i]-=zt;
54 wei[i^1]+=zt;
55 }
56 if (now==0) deep[x]=-2;
57 return now;
58 }
59 int main(){
60 freopen ("e.in","r",stdin);
61 freopen ("e.out","w",stdout);
62 int i,j,k,zt,ans=0;
63 scanf("%d%d%d",&m,&n,&c);
64 for (i=1;i<=n;i++)
65 scanf("%s",s[i]+1);
66 for (i=1;i<=c;i++)
67 scanf("%d",a+i);
68 tot=1;tt=MAX-5;
69 memset(head,0,sizeof(head));
70 for (i=1;i<=n;i++)
71 for (j=1;j<=m;j++){
72 if (s[i][j]=='B') ss=getid(i,j,1);
73 if (s[i][j]=='.')
74 addedge(getid(i,j,0),getid(i,j,1),oo);
75 if (s[i][j]>='a' && s[i][j]<='z')
76 addedge(getid(i,j,0),getid(i,j,1),a[s[i][j]-'a'+1]);
77 for (k=0;k<4;k++)
78 addedge(getid(i,j,1),getid(i+dx[k],j+dy[k],0),oo);
79 }
80 ans=0;
81 while (bfs()){
82 while (zt=dfs(ss,oo),zt){
83 ans+=zt;
84 if (ans>=1e9) goto away;
85 }
86 }
87 away:printf("%d",(ans<1e9?ans:-1));
88 return 0;
89
