#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
using pii=pair<int,int>;
int n,m,D,K,cnt;
int main(){
ios::sync_with_stdio(false); cin.tie(0);
cin>>n>>m>>D>>K;
vector<vector<char>> a(n+5,vector<char>(m+5));
vector<vector<int>> water(n+5,vector<int>(m+5)),diff(n+5,vector<int>(m+5));
vector<pii> S;
for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
cin>>a[i][j];
if(a[i][j]=='S'){
S.push_back({i,j});
}
}
}
//round 1
for(auto [i,j]:S){
int r1=max(1,i-D),r2=min(n,i+D);
int c1=max(1,j-D),c2=min(m,j+D);
diff[r1][c1]++; diff[r2+1][c1]--;
diff[r1][c2+1]--; diff[r2+1][c2+1]++;
}
for(int j=1;j<=m;j++){
for(int i=1;i<=n;i++){
diff[i][j]+=diff[i-1][j];
}
}
for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
diff[i][j]+=diff[i][j-1];
if(a[i][j]=='M' && diff[i][j]>=K) cnt++;
}
}
cout<<cnt<<endl;
}
