#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vl vector<ll>
#define vb vector<bool>
#define vs vector<string>
#define ed "\n"
#define fi first
#define se second
#define pll pair<ll, ll>
#define ff(aa, bb, cc) for(ll aa = bb; aa < cc; aa++)
#define pb push_back
#define all(aaa) aaa.begin(), aaa.end()
int main(){
ll n, m, d, k;
cin >> n >> m >> d >> k;
vs arr(n);
ff(i, 0, n){
cin >> arr[i];
}
vector<vl> psum(n+5, vl(m+5, 0));
ff(i, 0, n){
ff(j, 0, m){
if(arr[i][j] == 'S'){
ll xiz = max(0LL, j-d), xder = min(m, j+d+1);
ll yar = max(0LL, i-d), yab = min(n, i+d+1);
psum[yar][xiz]++;
psum[yab][xder]++;
psum[yar][xder]--;
psum[yab][xiz]--;
}
}
}
/*ff(i, 0, n){
ff(j, 0, m){
cout << psum[i][j] << " ";
}
cout << ed;
}
cout << ed;*/
ff(i, 0, n){
ff(j, 1, m){
psum[i][j] += psum[i][j-1];
}
}
/*ff(i, 0, n){
ff(j, 0, m){
cout << psum[i][j] << " ";
}
cout << ed;
}
cout << ed;*/
ff(i, 1, n){
ff(j, 0, m){
psum[i][j] += psum[i-1][j];
}
}
/*ff(i, 0, n){
ff(j, 0, m){
cout << psum[i][j] << " ";
}
cout << ed;
}
cout << ed;*/
ll c = 0;
ff(i, 0, n){
ff(j, 0, m){
if(arr[i][j] == 'M'){
if(psum[i][j] >= k){
c++;
}
}
}
}
cout << c;
return 0;
}
