#include <bits/stdc++.h>
using namespace std;
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")
#define pb push_back
#define ll long long
#define all(v) v.begin(),v.end()
int mod = 1e8;
const int N = 1e6;
const int inf = 2e9;
int w[600][600],w1[2][N + 100];
signed main(){
//freopen("shuffle.in", "r", stdin);
//freopen("shuffle.out", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
int n,m,d,k;
cin >> n >> m >> d >> k;
char a[n + 1][m + 1];
vector <pair <int,int>> v;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
cin >> a[i][j];
if(a[i][j] == 'S') v.pb({i,j});
}
}
if(n <= 500 && m <= 500){
int ans = 0;
for(auto to : v){
int x = to.first,y = to.second;
for(int i = max(1,x - d); i <= min(n,x + d); i++){
for(int j = max(1,y - d); j <= min(m,y + d); j++){
w[i][j]++;
}
}
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
if(a[i][j] == 'M' && w[i][j] >= k) ans++;
}
}
cout << ans;
}
else{
int ans = 0;
for(int j = 1; j <= m; j++){
if(a[1][j] == 'S'){
w1[1][max(1,j - d)]++,w1[1][min(m,j + d) + 1]--;
}
}
for(int j = 1; j <= m; j++){
w1[1][j] += w1[1][j - 1];
}
for(int j = 1; j <= m; j++){
if(a[1][j] == 'M' && w1[1][j] >= k) ans++;
}
cout << ans;
}
}
