#include <bits/stdc++.h>
using ll = long long;
using namespace std;
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
ll r, c, d, k;
cin >> r >> c >> d >> k;
set<pair<ll, ll>> s, m;
vector<vector<char>> adj(r, vector<char>(c));
if (r == 1) {
vector<ll> count(c + 1), pref(c + 1);
for (int i = 0; i < r; i++) {
for (int j = 0; j < c; j++) {
cin >> adj[i][j];
if (adj[i][j] == 'S') {
s.insert({i, j});
}
if (adj[i][j] == 'M') {
m.insert({i, j});
}
}
}
for (auto [x, y] : s) {
ll topl = max(0LL, y - d);
ll topr = min((c - 1), y + d);
count[topl]++;
count[topr + 1]--;
}
pref[0] = count[0];
for (int i = 1; i < c; i++) {
pref[i] = pref[i - 1] + count[i];
}
ll ans = 0;
for (auto [x, y] : m) {
if (pref[y] >= k) {
ans++;
}
}
cout << ans << "\n";
} else {
vector<vector<ll>> count(r, vector<ll>(c));
for (int i = 0; i < r; i++) {
for (int j = 0; j < c; j++) {
cin >> adj[i][j];
if (adj[i][j] == 'S') {
s.insert({i, j});
}
if (adj[i][j] == 'M') {
m.insert({i, j});
}
}
}
for (auto [x, y] : s) {
ll topl = max(0LL, y - d);
ll topr = min((c - 1), y + d);
ll downl = max(0LL, x - d);
ll downr = min((r - 1), x + d);
for (int i = downl; i <= downr; i++) {
for (int j = topl; j <= topr; j++) {
count[i][j]++;
}
}
}
ll ans = 0;
for (auto [x, y] : m) {
if (count[x][y] >= k) {
ans++;
}
}
cout << ans << "\n";
}
}
