#include <bits/stdc++.h>
#define int long long

using namespace std;

struct info {
    int x, y;
};

int m, n, d, k;
vector<info> market;
vector<info> house;


int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    freopen("KHUDANCU.INP", "r", stdin);
    freopen("KHUDANCU.OUT", "w", stdout);

    cin >> m >> n >> d >> k;

    for (int i = 1; i <= m; i += 1) {
        for (int j = 1; j <= n; j += 1) {
            char c;
            cin >> c;
            if (c == 'P') house.push_back({i, j});
            if (c == 'M') market.push_back({i, j});
        }
    }

    int res = 0;
    for (info a : house) {
        int check = 0;

        for (info b : market) {
            if (abs(a.x - b.x) <= d && abs(a.y - b.y) <= d) {
                check += 1;
                if (check >= k) {
                    res += 1;
                    break;
                }
            }
        }
    }

    cout << res;

    return 0;
}