#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#define rep(i, s, e) for (ll i = s; i < e; i++)
#define upmax(a, b) a = max(a, b)
#define upmin(a, b) a = min(a, b)
using namespace std;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;
using pll = pair<ll, ll>;
using vpll = vector<pll>;
void solve() {
ll n, m, D, K;
cin >> n >> m >> D >> K;
vvll arr(n, vll(m, 0));
vpll mushrooms;
rep(i, 0, n) {
rep(j, 0, m) {
char c;
cin >> c;
if (c == 'S') arr[i][j] = 1;
else if (c == 'M') mushrooms.push_back({ i, j });
}
}
vvll pref(n, vll(m));
pref[0][0] = arr[0][0];
rep(i, 1, m) pref[0][i] = pref[0][i - 1] + arr[0][i];
rep(i, 1, n) pref[i][0] = pref[i - 1][0] + arr[i][0];
rep(i, 1, n) {
rep(j, 1, m) {
pref[i][j] = pref[i][j - 1] + pref[i - 1][j] - pref[i - 1][j - 1] + arr[i][j];
}
}
ll ans = 0;
rep(i, 0, mushrooms.size()) {
ll x = mushrooms[i].first;
ll y = mushrooms[i].second;
ll x1 = max((ll)0, x - D);
ll x2 = min(n - 1, x + D);
ll y1 = max((ll)0, y - D);
ll y2 = min(m - 1, y + D);
// Calc the sum in the rectangle:
ll sum = pref[x2][y2];
if (y1 > 0) sum -= pref[x2][y1 - 1];
if (x1 > 0) sum -= pref[x1 - 1][y2];
if (x1 > 0 && y1 > 0) sum += pref[x1 - 1][y1 - 1];
if (sum >= K) ans++;
}
cout << ans << endl;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
solve();
}
