#include<bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define in insert
#define all(x) x.begin(),x.end()
#define pb push_back
#define eb emplace_back
#define ff first
#define ss second
#define int long long
typedef long long ll;
typedef vector<int> vi;
typedef set<int> si;
typedef multiset<int> msi;
typedef pair<int, int> pii;
typedef vector<pii> vpii;
template<typename T, typename U>
ostream & operator << (ostream &out, const pair<T, U> &c) {
out << c.first << ' ' << c.second;
return out;
}
template<typename T>
ostream & operator << (ostream &out, vector<T> &v) {
const int sz = v.size();
for (int i = 0; i < sz; i++) {
if (i) out << ' ';
out << v[i];
}
return out;
}
template<typename T>
istream & operator >> (istream &in, vector<T> &v) {
for (T &x : v) in >> x;
return in;
}
template<typename T>
void mxx(T &a, T b){if(b > a) a = b;}
template<typename T>
void mnn(T &a, T b){if(b < a) a = b;}
void go() {
int n, m, d, k;
cin >> n >> m >> d >> k;
vector<vector<int>> cnt(n + 10, vector<int>(m + 10, 0));
vector<vector<char>> g(n + 10, vector<char>(m + 10));
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
cin >> g[i][j];
if(g[i][j] == 'S') {
int id = i - d;
int l1 = j - d;
int r1 = j + d + 1;
mxx(l1, 1ll);
mnn(r1, m + 1);
mxx(id, 1ll);
cnt[id][l1]++;
cnt[id][r1]--;
id = i + d + 1;
mnn(id, n + 1);
cnt[id][l1]--;
cnt[id][r1]++;
}
}
}
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
cnt[i][j] += cnt[i][j - 1];
}
}
for(int i = 1; i <= m; i++) {
for(int j = 1; j <= n; j++) {
cnt[j][i] += cnt[j - 1][i];
}
}
int ans = 0;
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
if(cnt[i][j] >= k && g[i][j] == 'M') {
ans++;
}
}
}
cout << ans << '\n';
}
signed main() {
fast;
int t = 1;
// cin >> t;
while(t--) {
go();
}
return 0;
}
