#include<bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
const int maxn=8e7;
const int N=9e6+5;
const ull inf=1e18;
int hd[N],cnt,n,m,k,stx,sty,vis[N];
char s[3005][3005];
ull dis[N],len[N];
ull ans;
struct edge{
    int u,to,nxt;
}e[maxn];
void add(int u,int v){
    e[++cnt].nxt=hd[u];
    e[cnt].to=v;
    e[cnt].u=u;
    hd[u]=cnt;
}
int pos(int x,int y){
    return (x-1)*m+y;
}
queue<int>q;
void bfs(int x,int y){
    q.push(pos(x,y));
    vis[pos(stx,sty)]=1;
    dis[pos(stx,sty)]=0;
    while(!q.empty()){
        int u=q.front();
        q.pop();
        for(int i=hd[u];i;i=e[i].nxt){
            int v=e[i].to;
            if(dis[v]>=max(dis[u]+1,len[v]+1)){
                dis[v]=max(dis[u]+1,len[v]+1);
                if(!vis[v]){
                    vis[v]=1;
                    q.push(v);
                }
            }
        }
    }
}
int main(){
    scanf("%d%d%d",&n,&m,&k);
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            dis[pos(i,j)]=inf;
        }
    }
    for(int i=1;i<=k;i++){
        int x,y;
        scanf("%d%d",&x,&y);
        if(i==1) stx=x,sty=y;
        len[pos(x,y)]=k-i;
    }
    for(int i=1;i<=n;i++){
        scanf("%s",s[i]+1);
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if(s[i][j]=='#') continue;
            if(s[i-1][j]=='.'){
                add(pos(i,j),pos(i-1,j));
                add(pos(i-1,j),pos(i,j));
            }
            if(s[i][j-1]=='.'){
                add(pos(i,j),pos(i,j-1));
                add(pos(i,j-1),pos(i,j));
            }
            if(s[i+1][j]=='.'){
                add(pos(i,j),pos(i+1,j));
                add(pos(i+1,j),pos(i,j));
            }
            if(s[i][j+1]=='.'){
                add(pos(i,j),pos(i,j+1));
                add(pos(i,j+1),pos(i,j));
            }
        }
    }
    bfs(stx,sty);
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if(dis[pos(i,j)]==inf) continue;
            ans+=(dis[pos(i,j)]*dis[pos(i,j)]);
        }
    }
    cout<<ans<<endl;
    return 0;
}