#include <bits/stdc++.h>
using namespace std;
#define int long long
int r, c, d, k;
vector<pair<int,int>> vm, vs;
vector<vector<int>> ps;
signed main() {
ios::sync_with_stdio(0); cin.tie(0);
cin >> r >> c >> d >> k;
ps.assign(r+5, vector<int> (c+5, 0));
for (int i=0; i<r; ++i) {
string s; cin >> s;
for (int j=0; j<c; ++j) {
if (s[j] == 'S') {
vs.push_back({i, j});
}
if (s[j] == 'M') {
vm.push_back({i, j});
}
}
}
for (auto [a, b] : vs) {
int ul1 = max(0LL, a-d), ul2 = max(0LL, b-d);
int dr1 = min(r, a+d), dr2 = min(c, b+d);
// cout << a << " " << b << "\n";
// cout << " -> " << ul1 << " " << ul2 << " "<< dr1 << " "<< dr2 << "\n";
ps[ul1][ul2]++;
ps[dr1+1][ul2]--;
ps[ul1][dr2+1]--;
ps[dr1+1][dr2+1]++;
// for (int i = 0; i < r; ++i) {
// for (int j = 0; j < c; ++j) {
// cout << ps[i][j] << " ";
// }
// cout << "\n";
// }
// cout << "\n\n";
}
for (int i=1; i<r; ++i) {
for (int j=0; j<c; ++j) {
ps[i][j] += ps[i-1][j];
}
}
for (int i=0; i<r; ++i) {
for (int j=1; j<c; ++j) {
ps[i][j] += ps[i][j-1];
}
}
int ans = 0;
for (auto [a, b]: vm) {
if (ps[a][b] >= k) ans++;
}
cout << ans;
}
