#include<bits/stdc++.h>
using namespace std;
int n,m,d,k;
vector<pair<int,int>> pos;
int main()
{
ios::sync_with_stdio(false); cin.tie(0);
cin>>n>>m>>d>>k;
vector<vector<char>> mat(n+1,vector<char>(m+1));
vector<vector<int>> pref(n+1,vector<int>(m+1,0));
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= m; j++)
{
cin>>mat[i][j];
if(mat[i][j] == 'M') pos.push_back({i+d,j+d});
pref[i][j] = (mat[i][j]=='S') + pref[i-1][j] + pref[i][j-1] - pref[i-1][j-1];
}
}
int res = 0;
for(auto [i,j] : pos)
{
int r1 = min(i,n);
int c1 = min(j,m);
int r2 = max(r1-2*d,1);
int c2 = max(c1-2*d,1);
int cnt = pref[r1][c1] - pref[r2-1][c1] - pref[r1][c2-1] + pref[r2-1][c2-1];
if(cnt >= k) res++;
}
cout<<res;
}
