#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define pb push_back
#define emb emplace_back
#define emc emplace
#define pii pair<int,int>
#define pll pair<ll,ll>
#define F first
#define S second
template <class type_key, class type_val>
using um = unordered_map<type_key, type_val>;
template <class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template <class T>
using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;
struct coordinate {
int x{}, y{};
coordinate() = default;
coordinate( int _x, int _y ) {
x = _x, y = _y;
}
};
signed main(void)
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, m, d, k;
cin >> n >> m >> d >> k;
int pref[n+1][m+1];
for( int i = 0; i <= n; i++ )
pref[i][0] = pref[0][i] = 0;
vector<coordinate> msh;
for( int i = 1; i <= n; i ++ ) {
for( int j = 1; j <= m; j++ ) {
char c;
cin >> c;
pref[i][j] = pref[i-1][j] + pref[i][j-1] - pref[i-1][j-1];
pref[i][j] += (c == 'S');
if( c == 'M') {
msh.pb(coordinate(i,j));
}
}
}
int ans = 0;
for( int i = 0; i < msh.size(); i++ ) {
int x1, y1, x2, y2;
x1 = max(msh[i].x - d, 1);
y1 = max(msh[i].y - d, 1);
x2 = min(msh[i].x + d, n);
y2 = min(msh[i].y + d, m);
int cnt = pref[x2][y2] - pref[x2][y1-1] - pref[x1-1][y2] + pref[x1-1][y1-1];
if( cnt >= k ) {
ans++;
}
}
cout << ans;
return 0;
}
