#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
#include <vector>

using namespace std;

const int max1 = 3000, max2 = 1e5;
const int inf = 0x3f3f3f3f;

int n, m, k;
int num[max1 + 5][max1 + 5];
char Map[max1 + 5][max1 + 5];
int f[max1 + 5][max1 + 5], g[max1 + 5][max1 + 5];

struct Point
{
    int x, y;
    Point () {}
    Point ( int __x, int __y )
        { x = __x, y = __y; }
};

vector <Point> bin[max1 * max1 + max2];

int main ()
{
    int x, y, startx, starty;
    scanf("%d%d%d", &n, &m, &k);
    for ( int i = 1; i <= k; i ++ )
    {
        scanf("%d%d", &x, &y);
        num[x][y] = i;
        if ( i == 1 )
            startx = x, starty = y;
    }

    for ( int i = 1; i <= n; i ++ )
        scanf("%s", Map[i] + 1);
    
    memset(g, 0x3f, sizeof(g));
    f[startx][starty] = k, g[startx][starty] = 0;
    bin[0].push_back(Point(startx, starty));

    for ( int i = 0; i <= n * n + m; i ++ )
    {
        for ( auto now : bin[i] )
        {
            x = now.x, y = now.y;

            --x;
            if ( x >= 1 && Map[x][y] != '#' && g[x][y] == inf )
            {
                if ( num[x][y] && num[x][y] + 1 <= f[now.x][now.y] && f[now.x][now.y] - num[x][y] >= g[now.x][now.y] + 1 )
                    f[x][y] = num[x][y], g[x][y] = g[now.x][now.y] + 1 + f[now.x][now.y] - num[x][y], bin[g[x][y]].push_back(Point(x, y));
                else
                    f[x][y] = f[now.x][now.y], g[x][y] = g[now.x][now.y] + 1, bin[g[x][y]].push_back(Point(x, y));
            }
            ++x;

            ++x;
            if ( x <= n && Map[x][y] != '#' && g[x][y] == inf )
            {
                if ( num[x][y] && num[x][y] + 1 <= f[now.x][now.y] && f[now.x][now.y] - num[x][y] >= g[now.x][now.y] + 1 )
                    f[x][y] = num[x][y], g[x][y] = g[now.x][now.y] + 1 + f[now.x][now.y] - num[x][y], bin[g[x][y]].push_back(Point(x, y));
                else
                    f[x][y] = f[now.x][now.y], g[x][y] = g[now.x][now.y] + 1, bin[g[x][y]].push_back(Point(x, y));
            }
            --x;

            --y;
            if ( y >= 1 && Map[x][y] != '#' && g[x][y] == inf )
            {
                if ( num[x][y] && num[x][y] + 1 <= f[now.x][now.y] && f[now.x][now.y] - num[x][y] >= g[now.x][now.y] + 1 )
                    f[x][y] = num[x][y], g[x][y] = g[now.x][now.y] + 1 + f[now.x][now.y] - num[x][y], bin[g[x][y]].push_back(Point(x, y));
                else
                    f[x][y] = f[now.x][now.y], g[x][y] = g[now.x][now.y] + 1, bin[g[x][y]].push_back(Point(x, y));
            }
            ++y;

            ++y;
            if ( y <= m && Map[x][y] != '#' && g[x][y] == inf )
            {
                if ( num[x][y] && num[x][y] + 1 <= f[now.x][now.y] && f[now.x][now.y] - num[x][y] >= g[now.x][now.y] + 1 )
                    f[x][y] = num[x][y], g[x][y] = g[now.x][now.y] + 1 + f[now.x][now.y] - num[x][y], bin[g[x][y]].push_back(Point(x, y));
                else
                    f[x][y] = f[now.x][now.y], g[x][y] = g[now.x][now.y] + 1, bin[g[x][y]].push_back(Point(x, y));
            }
            --y;
        }
    }

    unsigned long long ans = 0;
    for ( int i = 1; i <= n; i ++ )
        for ( int j = 1; j <= m; j ++ )
            if ( g[i][j] != inf )
                ans += 1uLL * g[i][j] * g[i][j];
    
    printf("%llu\n", ans);

    return 0;
}