//Bismillah
#include <bits/stdc++.h>
using namespace std;
#define int long long
//@author: abdinabiev
const int N = 1e6 + 12, INF = 1e18;
signed main() {
ios::sync_with_stdio(false);
cin.tie(0);
int r, c, d, k;
cin >>r >>c >>d >>k;
vector<string> a(r + 1);
for (int i = 1; i <= r; ++i) {
string s; cin >>s;
a[i] = s;
}
vector<vector<int>> ps(r + 1, vector<int>(c + 1, 0));
for (int i = 1; i <= r; ++i) {
for (int j = 1; j <= c; ++j) {
if (a[i][j - 1] == 'S') ps[i][j] = 1;
}
}
for (int i = 1; i <= r; ++i) {
for (int j = 1; j <= c; ++j) {
ps[i][j] += ps[i - 1][j] + ps[i][j - 1] - ps[i - 1][j - 1];
}
}
int ans = 0;
for (int i = 1; i <= r; ++i) {
for (int j = 1; j <= c; ++j) {
if (a[i][j - 1] != 'M') continue;
int r1 = max((int)1, i - d);
int c1 = max((int)1, j - d);
int r2 = min(r, i + d);
int c2 = min(c, j + d);
int cnt = ps[r2][c2] - ps[r1 - 1][c2] - ps[r2][c1 - 1] + ps[r1 - 1][c1 - 1];
if (cnt >= k) ans++;
}
}
cout <<ans <<'\n';
}
