#pragma GCC optimize(2)
#pragma GCC optimize(3)
#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define debug(x) cout << #x << "=" << x << endl
// using i128 = __int128_t;
#define int unsigned long long
typedef pair<int, int> PII;
typedef long long ll;
inline void read(int &x)
{
    char ch = getchar();
    int f = 1;
    x = 0;
    while (!isdigit(ch) && ch ^ '-')
        ch = getchar();
    if (ch == '-')
        f = -1, ch = getchar();
    while (isdigit(ch))
        x = x * 10 + ch - '0', ch = getchar();
    x *= f;
}
void write(int x)
{
    if (x < 0)
        putchar('-'), x = -x;
    if (x > 9)
        write(x / 10);
    putchar(x % 10 + '0');
    return;
}
// int a[N];
const int N = 5e5 + 10;
const int mod = 1e9 + 7;
#define pre(i, a, b) for (int i = a; i <= b; i++)
int qmi(int a, int b)
{
    int res = 1;
    while (b)
    {
        if (b & 1)
            res = res * a % mod;
        a = a * a % mod;
        b >>= 1;
    }
    return res;
}
ll ans[N];
ll n, m, k;
ll tim[3010][3010];
char v[3010][3010];
ll dist[3010][3010];
ll dx[] = {1, -1, 0, 0};
ll dy[] = {0, 0, 1, -1};
ll vis[3010][3010];
ll st[3010][3010];
queue<PII> q;
void rCL()
{
    cin >> n >> m >> k;
    // cout<<n<<endl;
    // return;
    vector<PII> poi;
    int aa, bb;
    for (int i = 1; i <= k; i++)
    {
        int a, b;
        cin >> a >> b;
        poi.push_back({a, b});
        if (i == 1)
        {
            aa = a;
            bb = b;
            continue;
        }
        // if (i == 1)
        //     continue;
        // if (i != k)
            tim[a][b] = k - i + 1;
    }
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            cin >> v[i][j];
        }
    }

    vis[aa][bb] = 1;
    q.push({aa, bb});
    while (!q.empty())
    {
        int x = q.front().first;
        int y = q.front().second;
        q.pop();
        for (int i = 0; i < 4; i++)
        {
            int xx = x + dx[i];
            int yy = y + dy[i];
            if (xx < 1 || xx > n || yy<1 | yy> m || v[xx][yy] == '#' || vis[xx][yy])
                continue;
            if (dist[x][y] + 1 < tim[xx][yy])
                continue;
            q.push({xx, yy});
            vis[xx][yy] = 1;
            dist[xx][yy] = dist[x][y] + 1;
        }
    }
    if (poi.size() > 2)
        poi.pop_back();
    for (int i = 0; i < poi.size(); i++)
    {
        if (i == 0)
            continue;
        int a = poi[i].first;
        int b = poi[i].second;
        st[a][b] = 1;
        dist[a][b] = k + i - 2;
        q.push({a, b});
    }

    /////
    while (!q.empty())
    {
        int x = q.front().first;
        int y = q.front().second;
        q.pop();
        // cout<<xx<<" "<<yy<<endl;
        for (int i = 0; i < 4; i++)
        {
            int xx = x + dx[i];
            int yy = y + dy[i];
            if (xx < 1 || xx > n || yy<1 | yy> m || v[xx][yy] == '#' || st[xx][yy])
                continue;
            if (dist[x][y] + 1 < tim[xx][yy])
                continue;
            q.push({xx, yy});
            st[xx][yy] = 1;
            dist[xx][yy] = min(dist[xx][yy], dist[x][y] + 1);
        }
    }

    ///
    reverse(poi.begin(), poi.end());
    if (poi.size() > 2)
        poi.pop_back();
    for (auto [a, b] : poi)
    {
        for (int i = 0; i < 4; i++)
        {
            int xx = a + dx[i];
            int yy = b + dy[i];
            if (xx < 1 || xx > n || yy<1 | yy> m || v[xx][yy] == '#')
                continue;
            if (dist[xx][yy] + 1 < tim[a][b])
                continue;
            dist[a][b] = min(dist[xx][yy] + 1, dist[a][b]);
        }
    }
    int ans = 0;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            if (i == aa && j == bb)
            {
                continue;
            }
            int qwq = max(dist[i][j], (tim[i][j]));
            qwq = dist[i][j];
            ans += qwq * qwq;
        }
    }
    cout << ans << endl;
}
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int O_o = 1;
    // cin >> O_o;
    while (O_o--)
    {
        rCL();
    }
}