#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#define double long double
using namespace std;
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int r, c, d, k;
cin>>r>>c>>d>>k;
int arr[r+1][c+1];
bool mush[r+1][c+1];
for(int i = 0;i<=r;i++){
for(int j = 0;j<=c;j++){
arr[i][j] = 0;
mush[i][j] = false;
}
}
for(int i = 0;i<r;i++){
for(int j = 0;j<c;j++){
char s;
cin>>s;
if(s=='M') mush[i][j] = true;
else if(s=='S'){
int bottom = max(0, i-d);
int left = max(0, j-d);
int right = min(c-1, j+d);
int top = min(r-1, i+d);
//cout<<"("<<i<<", "<<j<<") "<<bottom<<left<<right<<top<<endl;
arr[bottom][left]++;
arr[bottom][right+1]--;
arr[top+1][left]--;
arr[top+1][right+1]++;
}
}
}
for(int i = 1;i<=r;i++){
arr[i][0]+=arr[i-1][0];
}
for(int i = 1;i<=c;i++){
arr[0][i]+=arr[0][i-1];
}
for(int i = 1;i<=r;i++){
for(int j = 1;j<=c;j++){
arr[i][j]-=arr[i-1][j-1];
arr[i][j]+=arr[i-1][j];
arr[i][j]+=arr[i][j-1];
}
}
int cnt = 0;
for(int i = 0;i<r;i++){
for(int j = 0;j<c;j++){
if(arr[i][j]>=k && mush[i][j]) cnt++;
}
}
cout<<cnt<<endl;
}
