#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 1e9 + 7;
#pragma GCC optimize("Ofast")
#define vi vector<int>
#define vll vector<ll>
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define fi first
#define sc second
#define endl '\n'
#define gl ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int r, c, d, k;
char x;
int main()
{
gl
cin >> r >> c >> d >> k;
int grid[r + 1][c + 1];
memset(grid, 0, sizeof(grid));
vector<pii > v;
for(int i = 1; i <= r; i++){
for(int j = 1; j <= c; j++){
cin >> x;
if(x == 'M')
v.pb({i, j});
if(x == 'S')
grid[i][j]++;
}
}
for(int i = 1; i <= r; i++){
for(int j = 1; j <= c; j++){
grid[i][j] += grid[i - 1][j] + grid[i][j - 1] - grid[i - 1][j - 1];
}
}
int ans = 0;
for(auto i : v){
int x = i.fi, y = i.sc;
pii L = make_pair(max(1, x - d), max(1, y - d));
pii R = make_pair(min(x + d, r), min(y + d, c));
ans += (grid[R.fi][R.sc] - grid[R.fi][L.sc - 1] - grid[L.fi - 1][R.sc] + grid[L.fi-1][L.sc-1] >= k);
}
cout << ans << endl;
}
