#include<bits/stdc++.h>
typedef long long ll;
using namespace std;


ll dp[3010][3010],f[3010][3010],t[3010][3010],flag[3010][3010];
char s[3010][3010];
ll n,m,k;
struct Node{
    ll x,y;
}qu[20000000];
ll px[4]={1,-1,0,0};
ll py[4]={0,0,1,-1};
ll ans;

void bfs(ll x,ll y){
    ll l=1,r=1;
    qu[l].x=x;qu[l].y=y;
    while(l<=r){
        Node t=qu[l];
        for(ll i=0;i<4;i++){
            ll tx=t.x+px[i],ty=t.y+py[i];
            if(tx>n||tx<=0||ty>m||ty<=0) continue;
            if(s[tx-1][ty-1]=='#') continue;
            //dp[tx][ty]=min(dp[tx][ty], s+1+dp[t.x][t.y]);
            if(dp[tx][ty]>1+dp[t.x][t.y]){
            	if(dp[tx][ty]==f[tx][ty]) continue;
                dp[tx][ty]=max(1+dp[t.x][t.y],f[tx][ty]);
                //flag[tx][ty]=1;
                r++;
                qu[r].x=tx;qu[r].y=ty;
            }
        }
        l++;
    }
}
void slove(){
    ll x0,y0;
    scanf("%lld%lld%lld",&n,&m,&k);
    for(ll i=1;i<=3000;i++){
        for(ll q=1;q<=3000;q++){
            dp[i][q]=1000000010;
        }
    } 
    for(ll i=1;i<=k;i++){
        ll x,y;
        scanf("%lld%lld",&x,&y);
        if(i==1) x0=x,y0=y;
        f[x][y]=k-i+1;
    }
    dp[x0][y0]=0;
    for(ll i=0;i<n;i++){
        scanf("%s",s[i]); 
    }
    bfs(x0,y0);
}
int main(){
    ll T=1;
    while(T--) slove();
    //ll MOD=1<<64;
    for(ll i=1;i<=n;i++)
    for(ll j=1;j<=m;j++){
        ll s=dp[i][j]!=1000000010 ? dp[i][j] : 0;
        ans+=s*s;
        //ans%=MOD;
    }
    //cout<<1;
    printf("%lld", ans);
    //cout<<ans;
    return 0;
}