#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 r, c, D, K;
cin >> r >> c >> D >> K;
vpll arrS; // Store sprinkles positions
vpll arrM; // Store mushrooms positions
rep(i, 0, r) {
rep(j, 0, c) {
char c;
cin >> c;
if (c == 'S') {
arrS.push_back({ i, j });
}
else if (c == 'M') {
arrM.push_back({ i, j });
}
}
}
ll n = arrS.size(); // Number of sprinkles
ll m = arrM.size(); // Number of mushrooms
sort(arrS.begin(), arrS.end());
sort(arrM.begin(), arrM.end());
ll x = arrM[0].first;
ll y = arrM[0].second;
multiset<ll> s;
ll left = -1, right = -1;
rep(i, 0, n) {
if (abs(x - arrS[i].first) <= D) {
if (left == -1) left = i;
right = i;
}
}
vll ans(m);
rep(i, max(left, (ll)0), min(n, right + 1)) {
if (abs(y - arrS[i].second) <= D) {
ans[0]++;
}
}
rep(i, 1, m) {
x = arrM[i].first, y = arrM[i].second;
//cout << "x = " << x << " y = " << y << endl;
ll idx = max(left, (ll)0);
while (idx < n) {
if (abs(x - arrS[idx].first) > D) {
idx++;
}
else break;
}
left = idx;
idx = right + 1;
while (idx < n) {
if (abs(x - arrS[idx].first) <= D) {
idx++;
}
else break;
}
right = idx - 1;
//cout << "left = " << left << " right = " << right << endl;
rep(j, max(left, (ll)0), min(n, right + 1)) {
if (abs(y - arrS[j].second) <= D) {
ans[i]++;
}
}
}
ll res = 0;
rep(i, 0, m) {
//cout << ans[i] << ' ';
if (ans[i] >= K) {
res++;
}
}
//cout << endl;
cout << res << endl;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
solve();
}
