#include<bits/stdc++.h>

#define X first
#define Y second
#define mp make_pair
#define pb push_back
#define pr pair
#define vc vector
#define sz(v) (int) v.size()
#define TASK ""

using namespace std;

typedef long long ll;
typedef long double ld;

const int Q = 20;
const int INF = 2e9;
const vector<int> dx = {0, 1, 0, -1}, dy = {1, 0, -1, 0};

int n, m, q;
vc<vc<int>> a, used, numb;
int c[Q];
pr<int, int> b[Q];
vc<int> g[Q];
int vis[Q];

bool in(int x, int y) {
    return 0 <= x && x < n && 0 <= y && y < m;
}

void bfs(int i, int x, int y) {
    queue<pr<int, int>> aye;
    aye.push(mp(x, y));
    used[x][y] = i;
    vc<int> curr;
    while (!aye.empty()) {
        x = aye.front().X, y = aye.front().Y;
        aye.pop();
        for (int d = 0; d < 4; ++d) {
            int nx = x + dx[d], ny = y + dy[d];
            if (in(nx, ny) && used[nx][ny] != i && a[nx][ny] != INF) {
                used[nx][ny] = i;
                if (numb[nx][ny]) {
                    curr.pb(numb[nx][ny]);
                } else {
                    aye.push(mp(nx, ny));
                }
            }
        }
    }
    for (int j : curr) g[i].push_back(j - 1);
}

void dfs(int i, vc<bool> &need, int col) {
    vis[i] = col;
    for (int j : g[i]) {
        if (need[j] && vis[j] != col) {
            dfs(j, need, col);
        }
    }
}

signed main() {
#ifdef LOCAL
	freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
#else
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif
	ios::sync_with_stdio(0);
	cin.tie(0);

	cin >> n >> m >> q >> b[0].X >> b[0].Y;
    --b[0].X, --b[0].Y;
	a.resize(n, vc<int>(m, INF));
	used.resize(n, vc<int>(m, -1));
	numb.resize(n, vc<int>(m, 0));
	for (int i = 0; i < n; ++i) {
        string s; cin >> s;
        for (int j = 0; j < m; ++j) if (s[j] == '.') a[i][j] = 0;
	}
	for (int i = 1; i <= q; ++i) {
        cin >> b[i].X >> b[i].Y >> c[i];
        --b[i].X, --b[i].Y;
        a[b[i].X][b[i].Y] = c[i];
	}
	for (int i = 0; i <= q; ++i) numb[b[i].X][b[i].Y] = i + 1;
	for (int i = 0; i <= q; ++i) bfs(i, b[i].X, b[i].Y);
	ll ans = 0;
    for (int mask = 1; mask < (1 << q); ++mask) {
        vc<bool> need(q + 1, false);
        ll sum = 0;
        for (int i = 0; i < q; ++i) {
            if ((1 << i) & mask) {
                need[i + 1] = true;
                sum += 1ll * c[i + 1];
            }
        }
        dfs(0, need, mask);
        bool flag = true;
        for (int i = 0; i <= q; ++i) {
            if (need[i] && vis[i] != mask) {
                flag = false;
                break;
            }
        }
        if (flag) ans = max(ans, sum);
    }
    cout << ans << "\n";

	return 0;
}