#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
const int maxN = 2e5 + 7;
void solve() {
int n, m, d, k;
cin >> n >> m >> d >> k;
char a[n + 1][m + 1];
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) cin >> a[i][j];
}
vector<vector<int>> pref(n + 1, vector<int>(m + 1, 0));
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
pref[i][j] = (a[i][j] == 'S') + pref[i - 1][j] + pref[i][j - 1] - pref[i - 1][j - 1];
}
}
auto get = [&](int x1, int y1, int x2, int y2) {
int pr = pref[x2][y2];
pr -= pref[x1 - 1][y2];
pr -= pref[x2][y1 - 1];
pr += pref[x1 - 1][y1 - 1];
return pr;
};
int ans = 0;
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
if(a[i][j] == 'M') {
int x1 = max(1LL, i - d);
int y1 = max(1LL, j - d);
int x2 = min(n, i + d);
int y2 = min(m, j + d);
int cnt = get(x1, y1, x2, y2);
if(cnt >= k) ans++;
}
}
}
cout << ans << '\n';
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//freopen("input.txt", "r", stdin);
int t = 1;
//cin >> t;
while(t--) solve();
}
