#include<bits/stdc++.h>

#define ull unsigned long long
#define vc vector
#define pb emplace_back
#define pii pair<int, int>
#define mkp make_pair
#define rep(i, a, b) for(int i = (a); i <= (b); ++i)
#define lep(i, a, b) for(int i = (a); i >= (b); --i)

using namespace std;

inline int read() {
	int x = 0, w = 0; char ch = getchar(); while(!isdigit(ch)) w |= (ch == '-'), ch = getchar();
	while(isdigit(ch)) x = x * 10 + (ch ^ 48), ch = getchar(); return w ? -x : x; 
}

const int N = 3005, inf = 1e9;
const int dx[5] = {1, -1, 0, 0}, dy[5] = {0, 0, 1, -1};

struct node { int x, y, z, d; bool friend operator < (node A, node B) { return A.d > B.d; } };
int n, m, k, sx, sy, a[N][N], f[N][N][2], vis[N][N][2];
ull ans;
char Map[N][N];

inline int ok(int x, int y) { return x > 0 && x <= n && y > 0 && y <= m && Map[x][y] == '.'; }

inline void dij() {
	priority_queue<node> Q; Q.push(node{sx, sy, 0, f[sx][sy][0] = 0});
	while(!Q.empty()) {
		auto [x, y, z, d] = Q.top(); Q.pop();
		if(vis[x][y][z]) continue; vis[x][y][z] = 1;
		if(z) {
			for(int i = 0, nx = x + dx[0], ny = y + dy[0]; i < 4; i++, nx = x + dx[i], ny = y + dy[i]) 
				if(ok(nx, ny) && f[nx][ny][1] > d + 1) Q.push(node{nx, ny, 1, f[nx][ny][1] = d + 1}); 
		}
		else {
			for(int i = 0, nx = x + dx[0], ny = y + dy[0]; i < 4; i++, nx = x + dx[i], ny = y + dy[i]) if(ok(nx, ny)) {
				if(a[nx][ny] && k - a[nx][ny] >= d + 1) {
					int nd = k - a[nx][ny] + 1;
					if(nd < f[nx][ny][1]) Q.push(node{nx, ny, 1, f[nx][ny][1] = nd});
				}
				else if(d + 1 < f[nx][ny][0]) Q.push(node{nx, ny, 0, f[nx][ny][0] = d + 1});
			}
		}
	}
}

signed main() {
	n = read(); m = read(); k = read();
	for(int i = 1, u, v; i <= k; i++) {
		u = read(), v = read(), a[u][v] = i;
		if(i == 1) sx = u, sy = v;
	}
	rep(i, 1, n) scanf("%s", Map[i] + 1);
	
	rep(i, 1, n) rep(j, 1, m) rep(k, 0, 1) f[i][j][k] = inf;
	
	dij();
	
	rep(i, 1, n) rep(j, 1, m) {
		int dis = min(f[i][j][0], f[i][j][1]);
		if(dis != inf) ans += 1ull * dis * dis;
	}
	cout << ans << endl;
	
	return 0;
}