#include <bits/stdc++.h>
using namespace std;
#define int long long
void solve(){
int r,c,d,k;
cin>>r>>c>>d>>k;
vector<vector<int>> g(r+1,vector<int>(c+1));
vector<vector<char>> ga(r+1,vector<char>(c+1));
for(int i=1;i<=r;i++){
for(int j=1;j<=c;j++){
char a;
cin>>a;
ga[i][j]=a;
//if(a=='M')g[i][j]+=0;
if(a=='S'){
int start_x=max((int)1,i-d),start_y=max((int)1,j-d);
int end_x=max((int)r,i+d),end_y=max((int)r,j+d);
g[start_x][start_y]++;
g[end_x][end_y]++;
g[start_x][end_y]--;
g[end_x][start_y]--;
}
}
}
int ans=0;
vector<vector<int>> prefix(r+1,vector<int>(c+1));
for(int i=1;i<=r;i++){
for(int j=1;j<=c;j++){
prefix[i][j]=g[i][j]
+prefix[i-1][j]
+prefix[i][j-1]
-prefix[i-1][j-1];
if(ga[i][j]=='M'&&prefix[i][j]>=k)ans++;
//cout<<prefix[i][j]<<" ";
}
//cout<<endl;
}
cout<<ans<<endl;
}
signed main(){
cin.tie(NULL);
cout.tie(NULL);
ios_base::sync_with_stdio(NULL);
int t=1;
//cin>>t;
while(t--)solve();
return 0;
}
/*
5 5 1 1
....M
.M...
..S..
.S...
...M.
*/
