#include <bits/stdc++.h>
using namespace std;
const int MAXN = 5e5 + 11;
char a[MAXN];
int dp[MAXN];
int r, c, d, k;
int id(int i, int j){
return i * c + j;
}
int main(){
cin >> r >> c >> d >> k;
for(int i = 0; i < r; i++){
for(int j = 0; j < c; j++){
cin >> a[i * c + j];
}
}
for(int i = 0; i < r; i++){
for(int j = 0; j < c; j++){
if(a[i * c + j] == 'S'){
int r1 = max(0, i - d), r2 = min(r - 1, i + d);
int c1 = max(0, j - d), c2 = min(c - 1, j + d);
dp[r1 * c + c1]++;
if(r2 != r - 1) dp[(r2 + 1) * c + c1]--;
if(c2 != c - 1) dp[r1 * c + (c2 + 1)]--;
if(r2 != r - 1 && c2 != c - 1) dp[(r2 + 1) * c + (c2 + 1)]++;
}
}
}
int ans = 0;
for(int i = 0; i < r; i++){
for(int j = 0; j < c; j++){
if(i > 0 && j > 0) dp[i * c + j] -= dp[(i - 1) * c + j - 1];
if(i > 0) dp[i * c + j] += dp[(i - 1) * c + j];
if(j > 0) dp[i * c + j] += dp[i * c + j - 1];
if(a[i * c + j] == 'M' && dp[i * c + j] >= k) ans++;
}
}
cout << ans << endl;
}
