#include <bits/stdc++.h>
using namespace std;
int main(){
int r,c,d,k;
cin >> r >> c >> d >> k;
char g[r+1][c+1];
int prefix[r+1][c+1];
int a[r+1][c+1];
for(int i=1;i<=r;i++){
for(int j=1;j<=c;j++){
cin >> g[i][j];
a[i][j] = 0;
if(g[i][j] == 'S'){
a[i][j]++;
}
}
}
for (int i = 1; i <= r; ++i){
for (int j = 1; j <= c; ++j){
prefix[i][j] = prefix[i-1][j] + prefix[i][j-1] - prefix[i-1][j-1] + a[i][j];
}
}
int cnt = 0;
for(int i=1;i<=r;i++){
for(int j=1;j<=c;j++){
if(g[i][j] == 'M'){
int s1 = max(1, i-d);
int s2 = max(1, j-d);
int e1 = min(r, i+d);
int e2 = min(c, j+d);
if((prefix[e1][e2] - prefix[s1-1][e2] - prefix[e1][s2-1] + prefix[s1-1][s2-1]) >= k){
cnt++;
}
}
}
}
cout << cnt;
}
