#include "bits/stdc++.h"
using namespace std;
vector< vector<long long> > Acumular;
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
long long n, m, d, k;
cin>>n>>m>>d>>k;
vector<string> Matriz(n);
Acumular.assign(n + 1, vector<long long>(m + 1, -0));
for(long long i = 0; i < n; i++) cin>>Matriz[i];
for(long long i = 0; i < n; i++){
for(long long j = 0; j < m; j++){
Acumular[i + 1][j + 1] = Matriz[i][j] == 'S';
Acumular[i + 1][j + 1] += Acumular[i + 1][j] + Acumular[i][j + 1] - Acumular[i][j];
}
}
/*for(auto E: Acumular){
for(auto e: E) cout<<e<<" ";
cout<<"\n";
}*/
long long c = -0;
for(long long i = 0; i < n; i++){
for(long long j = 0; j < m; j++){
if(Matriz[i][j] != 'M') continue;
long long i1 = min(i + 1 + d, n), j1 = min(j + 1 + d, m);
long long i2 = max(i - d, 0LL), j2 = max(j - d, 0LL);
//cout<<i1<<" "<<i2<<" "<<j1<<" "<<j2<<" "<<Acumular[i1][j1]<<" "<<-Acumular[i1][j2]<<" "<<-Acumular[i2][j1]<<" "<<Acumular[i2][j2]<<"\n";
long long Obtener = Acumular[i1][j1] - Acumular[i1][j2] - Acumular[i2][j1] + Acumular[i2][j2];
c += Obtener >= k;
}
}
cout<<c;
return 0;
}
