#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 w1[2][N];
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];
int w[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});
w[i][j] = w1[i][j] = 0;
w[0][j] = w[i][0] = 0;
}
}
for(auto to : v){
int x = to.first,y = to.second;
w[max(1,x - d)][max(1,y - d)]++;
w[min(n,x + d) + 1][max(1,y - d)]--;
w[max(1,x - d)][min(m,y + d)]++;
w[min(n,x + d) + 1][min(m,y + d)]--;
}
for(int j = 1; j <= m; j++){
for(int i = 1; i <= n; i++){
w[i][j] += w[i - 1][j];
}
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
w[i][j] += w[i][j - 1];
}
}
int ans = 0;
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;
}
