#include <bits/stdc++.h>
// #pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
// #pragma GCC optimize("Ofast")
// #pragma GCC target("avx,avx2,fma")
// #pragma GCC optimization("unroll-loops")
// #pragma ("reroll")
#define all(v) v.begin(), v.end()
#define skip continue;
#define gold ios_base::sync_with_stdio(false);cin.tie(NULL);
#define xa "\n"
#define int long long
#define pb push_back
#define S second
#define F first
using namespace std;
const int mod = 1e9 + 7;
const int N = 1e5 + 7;
const int MAX = 1e9;
const int inf = 1e18;
int gcd(int a, int b) { if (b == 0) return a; else if(a == 0) return b; else return gcd(b, a % b); }
int lcm(int a, int b) { return a / gcd(a, b) * b; }
void solve() {
int n, m, d, k;
cin >> n >> m >> d >> k;
char c[n + 1][m + 1];
int sl[n + 2][m + 2];
for(int i = 0; i <= n + 1; i++){
for(int j = 0; j <= m + 1; j++){
sl[i][j] = 0;
}
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
cin >> c[i][j];
if(c[i][j] == 'S'){
for(int l = max(1ll, i - d); l <= min(n, i + d); l++){
int k1 = max(1ll, j - d);
int k2 = min(m, j + d) + 1;
sl[l][k1]++;
sl[l][k2]--;
}
}
}
}
int cur = 0;
int ans = 0;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
cur += sl[i][j];
if(c[i][j] == 'M' && cur >= k) {
ans++;
}
}
cur += sl[i][m + 1];
}
cout << ans;
}
signed main() {
gold;
//freopen("knight.in", "r", stdin);
//freopen("knight.out", "w", stdout);
int t = 1;
int tt = 0;
//cin >> t;
while (t--) {
tt++;
//cout << "Case " << tt << ":" << xa;
solve();
}
}
