/* Ajay Jadhav */
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <deque>
#include <vector>
#include <cstdlib>
#include <iomanip>
#include <cmath>
#include <queue>
#include <map>
#include <set>
#include <stack>
#include <ctime>
#include <string.h>
#include <climits>
#include <cstring>
using namespace std;
#define ll long long
#define pb push_back
#define pii pair<int, int>
#define vi vector<int>
#define vvi vector<vi>
#define vii vector<pii>
#define mi map<int, int>
#define mii map<pii, int>
#define all(a) (a).begin(), (a).end()
#define x first
#define y second
#define sz(x) (int)x.size()
#define hell 1000000007
#define rep(i, a, b) for (int i = a; i < b; i++)
#define endl '\n'
void solve()
{
int r, c, d, k;
cin >> r >> c >> d >> k;
vvi mat(r + 5, vi(c + 5));
vvi mushrooms;
rep(i, 0, r)
{
string s;
cin >> s;
rep(j, 0, c)
{
if (s[j] == 'M')
mushrooms.pb({i, j});
else if (s[j] == 'S')
{
// 2d range update...
int r1, r2, c1, c2;
r1 = max(0, i - d);
r2 = min(r - 1, i + d);
c1 = max(0, j - d);
c2 = min(c - 1, j + d);
for (int i = r1; i <= r2; i++)
{
mat[i][c1] += 1;
mat[i][c2 + 1] -= 1;
}
}
}
}
rep(i, 0, r + 1)
{
rep(j, 0, c + 1)
{
if (j > 0)
mat[i][j] += mat[i][j - 1];
}
}
int ans = 0;
rep(i, 0, sz(mushrooms))
{
if (mat[mushrooms[i][0]][mushrooms[i][1]] >= k)
{
ans++;
}
}
cout << ans << endl;
}
signed main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int t = 1;
// cin>>t;
while (t--)
{
solve();
}
return 0;
}
