#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pll pair<ll,ll>
#define pii pair<int,int>
#define fs first
#define sc second
#define tlll tuple<ll,ll,ll>
int R,C,K,D;
vector<vector<int>> arr,mush;
vector<string> v;
int main(){
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin>>R>>C>>D>>K;
arr = mush = vector<vector<int>>(R+1,vector<int>(C+1,0));
v = vector<string>(R+1);
for(int i = 0;i<R;i++){
cin>>v[i];
for(int j = 0;j<C;j++){
if(v[i][j] == 'S'){
int rl = i-D,rr = i+D+1;
int cl = j-D,cr = j+D+1;
cl = max(0,cl),cr = min(cr,C);
rl = max(0,rl),rr = min(rr,R);
arr[rl][cl]++,arr[rl][cr]--;
arr[rr][cl]--,arr[rr][cr]++;
}
else if(v[i][j] == 'M'){
mush[i][j] = 1;
}
}
}
int ans = 0;
vector<int> now(C+1,0);
for(int i = 0;i<R;i++){
int pref = 0;
for(int j = 0;j<=C;j++){
pref += arr[i][j];
now[j] += pref;
ans += (mush[i][j])*(now[j]>=K);
}
}
cout<<ans;
}
