// #pragma GCC optimize(2, "Ofast", "inline")
#include <bits/stdc++.h>
// using pair<int,int>= pair<int,int>;
// using tuple<int,int,int>= tuple<int,int,int>;
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<pair<int,int>> snack(k);
    // map<pair<int,int>, int> mp;
    vector<int> mp(n * m + 1000, 0);
    for(int i = 0; i < k; i++) {
        cin >> snack[i].first >> snack[i].second;
        snack[i].first--;
        snack[i].second--;
        if(i)mp[snack[i].first * m + snack[i].second] = 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].first+ dx[i] == snack[0].first && snack[1].second + dy[i] == snack[0].second) {
            odir = i;
        }
    }

    vector<int> f(n * m, inf);
    // f[snack[0].first][snack[0].second] = 0;
    deque<tuple<int,int,int>> pq;
    pq.push_back({0, odir, snack[0].first * m + snack[0].second});
    vector<vector<pair<int, int>>> v(n * m + 1);
    while(!pq.empty()) {
        auto [d, dir, pos] = pq.front();
        pq.pop_front();

        if(!v[d].empty()) {
            for(int i = 0; i < int(v[d].size()); i++) {
                auto [a, b] = v[d].back();
                v[d].pop_back();
                pq.push_front({d, a, b});
            }
        }

        int x = pos / m;
        int y = pos % m;
        if(f[pos] != inf) {
            continue;
        }
        // cerr << x + 1 << " " << y + 1 << " " << d << endl;
        f[pos] = 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;
                // cerr << mp[nx * m + ny] << endl;
            if(mp[nx * m + ny] > d + 1) {
                v[mp[nx * m + ny]].push_back({i, nx * m + ny});
            } else {
                pq.push_back({d + 1, i, nx * m + ny});
            }
            // cout << nx << " " << ny << endl;
        }
    }

    int tim = k - 2;
    tim = max(0, tim);
    queue<tuple<int,int,int>> q;
    q.push({snack[0].first, snack[0].second, tim});
    vector<int> dis(n * m, inf);
    dis[snack[0].first * m + snack[0].second] = 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]);
        }
        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();
}