#include <bits/stdc++.h>
#define fast ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL)
#define ll long long int
#define ld long double
using namespace std;
const int N = 1e6 + 5;
const int MOD = 1e9 + 7;
int main(){
fast;
int n, m, d, k;
cin >> n >> m >> d >> k;
char a[n + 1][m + 1];
int pre_sum[n + 1][m + 1];
memset(pre_sum, 0, sizeof pre_sum);
for(int i = 1; i <= n; ++i){
for(int j = 1; j <= m; ++j){
cin >> a[i][j];
pre_sum[i][j] = pre_sum[i - 1][j] + pre_sum[i][j - 1] - pre_sum[i - 1][j - 1];
if(a[i][j] == 'S')
++pre_sum[i][j];
}
}
int ans = 0;
for(int i = 1; i <= n; ++i){
for(int j = 1; j <= m; ++j){
if(a[i][j] == 'M'){
int x = max(1, j - d), y = min(m, j + d), x1 = max(1, i - d), y1 = min(n, i + d);
if((pre_sum[y1][y] - pre_sum[x1 - 1][y] - pre_sum[y1][x - 1] + pre_sum[x1 - 1][x - 1]) >= k)
++ans;
}
}
}
cout << ans << '\n';
return 0;
}
