#include <bits/stdc++.h>
using namespace std;
const int N = 5e5+7;
int numRow, numCol, maxDist, minNum;
vector<int> a[N];
string s[N];
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
#ifdef NHPHUCQT
freopen("demo.inp", "r", stdin);
freopen("demo.out", "w", stdout);
#endif // NHPHUCQT
cin >> numRow >> numCol >> maxDist >> minNum;
for (int i = 0; i <= numRow+3; ++i) {
a[i].resize(numCol+3, 0);
}
for (int i = 1; i <= numRow; ++i) {
cin >> s[i];
s[i] = '0' + s[i];
}
for (int i = 1; i <= numRow; ++i)
for (int j = 1; j <= numCol; ++j) {
// s[i][j]
if (s[i][j] == 'S') {
int x = max(1, i - maxDist);
int y = max(1, j - maxDist);
int u = min(numRow, i + maxDist);
int v = min(numCol, j + maxDist);
a[x][y]++;
a[x][v+1]--;
a[u+1][y]--;
a[u+1][v+1]++;
}
}
for (int i = 1; i <= numRow; ++i)
for (int j = 1; j <= numCol; ++j) {
a[i][j] += a[i][j-1];
}
for (int j = 1; j <= numCol; ++j)
for (int i = 1; i <= numRow; ++i) {
a[i][j] += a[i-1][j];
}
int res = 0;
for (int i = 1; i <= numRow; ++i)
for (int j = 1; j <= numCol; ++j) {
if (s[i][j] == 'M') {
res += a[i][j] >= minNum;
}
}
cout << res;
return 0;
}
