#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> intset;
int n,m,d,k,con=0;
int main(){
mt19937 rng(chrono::steady_clock().now().time_since_epoch().count());
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
cin >> n >> m >> d >> k;
vector<vector<char>> garden(n+1,vector<char>(m+1));
vector<vector<int>> psum(n+1,vector<int>(m+1));
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
cin >> garden[i][j];
if(garden[i][j]=='S'){
psum[max(i-d,0)][max(j-d,0)]++;
psum[min(i+d+1,n)][min(j+d+1,m)]++;
psum[max(i-d,0)][min(j+d+1,m)]--;
psum[min(i+d+1,n)][max(j-d,0)]--;
}
}
}
for(int i=0;i<n;i++){
for(int j=1;j<m;j++){
psum[i][j]+=psum[i][j-1];
}
}
for(int i=1;i<n;i++){
for(int j=0;j<m;j++){
psum[i][j]+=psum[i-1][j];
}
}
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
//cout << psum[i][j] << " ";
if(garden[i][j]=='M' && psum[i][j]>=k){
con++;
}
}
//cout << endl;
}
cout << con;
}
