#define fast ios::sync_with_stdio(false); cin.tie(0)
#define foru(i, k, n) for (int i = k; i < n; i++)
#define ford(i, k, n) for (int i = k; i >= n; i--)
#define pb push_back
#define ff first
#define ss second
#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <map>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
int n, m, d, k;
vector<string> board;
vector<vector<ll>> pre;
int query(int _i, int _j) {
int i1 = max(0, _i - d), j1 = max(0, _j - d), i2 = min(n - 1, _i + d), j2 = min(m - 1, _j + d);
if (i1 > i2 || j1 > j2)
return 0;
if (i1 && j1)
return pre[i2][j2] + pre[i1 - 1][j1 - 1] - pre[i1 - 1][j2] - pre[i2][j1 - 1];
else if (!i1 && !j1)
return pre[i2][j2];
else if (!i1)
return pre[i2][j2] - pre[i2][j1 - 1];
else
return pre[i2][j2] - pre[i1 - 1][j2];
}
int main() {
fast;
cin >> n >> m >> d >> k;
pre.resize(n);
foru(i, 0, n) {
pre[i].assign(m, 0);
string s;
cin >> s;
board.pb(s);
}
foru(i, 0, n) {
foru(j, 0, m) {
if (!i && !j)pre[i][j] = (board[i][j] == 'S');
else if (!i)pre[i][j] = (pre[i][j - 1] + (board[i][j] == 'S'));
else if (!j)pre[i][j] = (pre[i - 1][j] + (board[i][j] == 'S'));
else pre[i][j] = (pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + (board[i][j] == 'S'));
}
}
int ret = 0;
foru(i, 0, n) {
foru(j, 0, m) {
if (board[i][j] == 'M')
ret += (query(i, j) >= k);
}
}
cout << ret;
return 0;
}
