#include <bits/stdc++.h>
using namespace std;
int main(){
int r, c, n, m;
cin>>r>>c>>n>>m;
string s;
vector <pair<int, int> > mushrooms;
vector<vector<int> > vect;
vect.resize(r+1, vector<int>(c+1, 0));
vector <vector<int> > psum;
psum.resize(r+1, vector<int>(c+1, 0));
for (int i=0; i<r; ++i){
cin>>s;
for (int j=0; j<c; ++j){
if (s[j]=='M'){
mushrooms.push_back(make_pair(i+1, j+1));
}
else if (s[j]=='S'){
++vect[i+1][j+1];
}
vect[i+1][j+1]+=vect[i+1][j];
}
}
for (int j=1; j<=c; ++j){
for (int i=1; i<=r; ++i){
psum[i][j] = psum[i-1][j]+vect[i][j];
}
}
int f = 0;
for (auto mush:mushrooms){
int count = psum[min(mush.first+n, r)][min(mush.second+n, c)]+psum[max(mush.first-n-1, 0)][max(mush.second-n-1, 0)]-psum[max(mush.first-n-1, 0)][min(mush.second+n, c)]-psum[min(mush.first+n, r)][max(mush.second-n-1, 0)];
if (count>=m){
++f;
}
}
cout<<f;
}
