#include <bits/stdc++.h>
using ll = long long;
using ull = unsigned long long;
using namespace std;
const int inf = 1e9;
int dx[4] = {0, 1, 0, -1};
int dy[4] = {1, 0, -1, 0};
void solve()
{
    int n, m, k;
    cin >> n >> m >> k;

    vector<array<int, 2>> snack(k);
    // map<array<int, 2>, int> mp;
    vector<int> mp(n * m, 0);
    for (int i = 0; i < k; i++)
    {
        cin >> snack[i][0] >> snack[i][1];
        snack[i][0]--;
        snack[i][1]--;
        if (i)
            mp[snack[i][0]* m + snack[i][1]] = k - i;
    }

    vector<string> qizi(n);
    for (int i = 0; i < n; i++)
    {
        cin >> qizi[i];
    }

    int odir = -1;
    for (int i = 0; i < 4; i++)
    {
        if (snack[1][0] + dx[i] == snack[0][0] && snack[1][1] + dy[i] == snack[0][1])
        {
            odir = i;
        }
    }

    vector<array<int, 4>> f(n * m, {inf, inf, inf, inf});
    // f[snack[0][0]][snack[0][1]] = 0;
    priority_queue<array<int, 3>, vector<array<int, 3>>, greater<>> pq;
    pq.push({0, odir, snack[0][0] * m + snack[0][1]});
    while (!pq.empty())
    {
        auto [d, dir, pos] = pq.top();
        pq.pop();
        int x = pos / m;
        int y = pos % m;
        if (f[pos][dir] != inf)
        {
            continue;
        }
        // cerr << x + 1 << " " << y + 1 << " " << d << endl;
        f[pos][dir] = d;
        for (int i = 0; i < 4; i++)
        {
            if (dir == (i + 2) % 4)
                continue;
            int nx = x + dx[i];
            int ny = y + dy[i];
            if (nx < 0 || nx >= n || ny < 0 || ny >= m || qizi[nx][ny] == '#')
                continue;
            pq.push({max(mp[nx*m+ny], d + 1), i, nx * m + ny});
            // cout << nx << " " << ny << endl;
        }
    }

    int tim = k - 2;
    tim = max(0, tim);
    queue<array<int, 3>> q;
    q.push({snack[0][0], snack[0][1], tim});
    vector<int> dis(n * m, inf);
    dis[snack[0][0] * m + snack[0][1]] = tim;
    while (!q.empty())
    {
        auto [x, y, d] = q.front();
        q.pop();

        for (int i = 0; i < 4; i++)
        {
            int nx = x + dx[i];
            int ny = y + dy[i];
            if (nx < 0 || nx >= n || ny < 0 || ny >= m || qizi[nx][ny] == '#')
                continue;
            if (dis[nx * m + ny] == inf)
            {
                dis[nx * m + ny] = min(d + 1, dis[nx * m + ny]);
                q.push({nx, ny, d + 1});
            }
        }
    }

    ull res = 0;
    for (int i = 0; i < n * m; i++)
    {
        int ans = dis[i];
        for (int j = 0; j < 4; j++)
        {
            ans = min(ans, f[i][j]);
        }
        if (ans == inf)
        {
            ans = 0;
        }
        // cerr << ans << " \n"[(i + 1) % m == 0];
        res += 1ll * ans * ans;
    }

    cout << res << "\n";
}
signed main()
{
    std::ios::sync_with_stdio(0);
    std::cin.tie(0);
    std::cout.tie(0);
    int tt = 1;
    // std::cin >> tt;
    while (tt--)
        solve();
}