#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
using namespace std;
int r, c;
vector<vector<int>> bit;
vector<pair<int, int>> shrooms;
void update(int x, int y) {
for (; x <= r; x += (x & (-x))) for (; y <= c; y += (y & (-y))) bit[x][y]++;
}
int query(int x, int y) {
int ans = 0;
for (; x; x -= (x & (-x))) for (; y; y -= (y & (-y))) ans += bit[x][y];
return ans;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int d, k;
cin >> r >> c >> d >> k;
bit.resize(r + 1);
FOR(i, 1, r + 1) bit[i].resize(c + 1);
FOR(i, 1, r + 1) {
FOR(j, 1, c + 1) {
char c;
cin >> c;
if (c == 'S') update(i, j);
else if (c == 'M') shrooms.push_back({i, j});
}
}
int ans = 0;
for (pair<int, int> i : shrooms) {
int x1 = min(r, i.first + d), x2 = max(0, i.first - d - 1), y1 = min(c, i.second + d), y2 = max(0, i.second - d - 1);
int cnt = query(x1, y1) - query(x2, y1) - query(x1, y2) + query(x2, y2);
if (cnt >= k) ans++;
}
cout << ans;
return 0;
}
