#include <bits/stdc++.h>
using namespace std;
#define vi vector<int>
#define vll vector<long long>
#define pb push_back
using ll= long long;
#define fast_io ios::sync_with_stdio(0); cin.tie(0)
#define inpint(x) int x; cin>>x
#define inpll(x) long long x; cin>>x
#define fl(i, n) for(int i=0; i<n; i++)
#define fl_1(i, n) for(int i=1; i<=n; i++)
#define int long long
#define pi pair<int, int>
#define mp make_pair
#define ld long double
void solve()
{
int r, c, d, k;
cin>>r>>c>>d>>k;
vector<pi> mushrooms(0);
vector<vector<int>> sp_pre(r+1, vector<int>(c+1, 0));
for(int i=1; i<=r; i++)
{
for(int j=1; j<=c; j++)
{
char a;
cin>>a;
sp_pre[i][j] = sp_pre[i-1][j] + sp_pre[i][j-1] - sp_pre[i-1][j-1];
if(a=='M')
{
mushrooms.pb(mp(i, j));
}
else if(a=='S')
{
sp_pre[i][j]++;
}
}
}
int ans{};
for(auto i: mushrooms)
{
pi tl = mp(max((int)1, i.first-d), max((int)1, i.second-d));
pi br = mp(min(r, i.first+d), min(c, i.second+d));
int nmus = sp_pre[br.first][br.second] - sp_pre[tl.first-1][br.second] - sp_pre[br.first][tl.second-1] + sp_pre[tl.first-1][tl.second-1];
if(nmus>=k) ans++;
}
cout<<ans<<"\n";
}
int32_t main()
{
fast_io;
int t=1;
//cin>>t;
while(t--)
{
solve();
}
}
