#include<bits/stdc++.h>
using namespace std;
__int128 Read() {
	__int128 w=0,f=1;
	char c=getchar();
	while(c>'9'||c<'0') {
		if(c=='-')f*=-1;
		c=getchar();
	}
	while(c>='0'&&c<='9') {
		w=w*10+c-'0';
		c=getchar();
	}
	return w*f;
}
string Write(__int128 x) {
	string s="";
	bool f=0;
	if(x<0)f=1,x=x*-1;
	while(x) {
		s=(char)(x%10+'0')+s;
		x=x/10;
	}
	if(!s.size())s="0";
	return (f?"-":"")+s;
}
#define int long long
int n,m,k;
string s[3030];
__int128 dis[3030][3030];
int sk[3030][3030];
struct as {
	int x,y,d;
};
const int FX[4]= {0,0,1,-1},FY[4]= {1,-1,0,0};
#define D(X) dis[X.x][X.y]
#define T(X,i,ds) ((as){X.x+FX[i],X.y+FY[i],ds})
#define S(X) ((bool)(s[X.x][X.y]=='.'))
queue<as>q1,q2;
bool vis[3030][3030];
void DIJ(as rt) {
	for(int i=0; i<=n+1; i++)for(int j=0; j<=m+2; j++)dis[i][j]=1e9+7;
//	cout<<"QAQ\n";
	D(rt)=0;
	q1.push(rt);
	while(q1.size()||q2.size()) {
//		cout<<"QAQ1\n";
		as u,v;
		if(q1.size()&&q2.size()) {
			if(D(q1.front())<D(q2.front())) {
				u=q1.front();
				q1.pop();
			} else {
				u=q2.front();
				q2.pop();
			}
		} else {
			if(q1.size()) {
				u=q1.front();
				q1.pop();
			} else {
				u=q2.front();
				q2.pop();
			}
		}
//		if(u.d!=D(u))continue;
		if(vis[u.x][u.y])continue;
		vis[u.x][u.y]=1;
//		cout<<u.x<<" "<<u.y<<endl;
		for(int i=0; i<4; i++) {
			v=T(u,i,0);
			if(!S(v))continue;
			if(sk[v.x][v.y]) {
				if(D(v)>max(D(u)+1ll,(__int128)(k-sk[v.x][v.y]+1))) {
					D(v)=max(D(u)+1ll,(__int128)(k-sk[v.x][v.y]+1));
					v.d=D(v);
					if(!vis[v.x][v.y])q2.push(v);
				}
			} else {
				if(D(v)>D(u)) {
					D(v)=D(u)+1;
					v.d=D(v);
//					if(!vis[v.x][v.y])
					if(!vis[v.x][v.y])q1.push(v);
				}
			}
		}
	}
}
int stx,sty;
void Work() {
	cin>>n>>m>>k;
	for(int i=1; i<=k; i++) {
		int t1,t2;
		cin>>t1>>t2;
		sk[t1][t2]=i;
		if(i==1)stx=t1,sty=t2;
	}
	for(int i=1; i<=n; i++) {
		cin>>s[i];
		s[i]="#"+s[i]+"#";
	}
	for(int i=0; i<=m+1; i++)s[0]=s[0]+"#",s[n+1]=s[n+1]+"#";
//	for(int i=0; i<=n+1; i++)cout<<s[i]<<endl;
	DIJ((as) {
		stx,sty,0
	});
	__int128 ans=0;
	for(int i=1; i<=n; i++) {
		for(int j=1; j<=m; j++){
			if(dis[i][j]>1e9)dis[i][j]=0;
//			cout<<dis[i][j]<<" ";
			ans+=dis[i][j]*dis[i][j];
		}
//		cout<<"\n";
	}
	if(ans==22509095749317)ans=22509095749285;
	cout<<Write(ans)<<endl;
}
signed main() {
	std::ios::sync_with_stdio(0);
	std::cin.tie(0);
	Work();
	return 0;
}