#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>;
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;
char c[n+1][m+1];
vector<array<int,4>> evs;
for( int i = 1; i <= n; i++ ) {
for( int j = 1; j <= m; j++ ) {
cin >> c[i][j];
if( c[i][j] == 'S') {
int col1 = max(j - d, 1);
bool k = (j + d + 1 > m);
int col2 = min(j + d + 1, m);
for( int row = max(1, i-d); row <= min(i+d,n); row++ ) {
evs.pb({row,col1,0,+1});
if( k ) evs.pb({row,col2,2,-1});
else evs.pb({row,col2,0,-1});
}
}
else if( c[i][j] == 'M') {
evs.pb({i,j,1,0});
}
}
}
sort(evs.begin(), evs.end());
int spr = 0;
int ans = 0;
for( int i = 0; i < evs.size(); i++ ) {
if( evs[i][2] == 1 ) {
if( spr >= k ) ans++;
} spr += evs[i][3];
}
cout << ans;
return 0;
}
