#include <bits/stdc++.h>
using namespace std;
#define ll long long int
#define ld long double
#define vi(x) vector<x>
#define pb push_back
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()
using pi = pair<int,int>;
#define f first
#define s second
#define mp make_pair
int main()
{
cin.tie(nullptr)->ios_base::sync_with_stdio(false);
int r,c,d,k;cin >> r >> c >> d >> k;
vector<vector<int>> ps(r+1,vector<int>(c+1));
vector<vector<char>> a(r+1,vector<char>(c+1));
for(int i=1;i<=r;i++){
for(int j=1;j<=c;j++){
cin >> a[i][j];
ps[i][j] = (a[i][j] == 'S');
ps[i][j]+=ps[i-1][j]+ps[i][j-1]-ps[i-1][j-1];
}
}
int ans = 0;
for(int i=1;i<=r;i++){
for(int j=1;j<=c;j++){
if(a[i][j] == 'M'){
int i1 = max(i-d,1),j1 = max(j-d,1),i2 = min(r,i+d),j2 = min(c,j+d);
//cout << i1 << ',' << j1 << '|' << i2 << ',' << j2 << '\n';
ans+=(ps[i2][j2]-ps[i1-1][j2]-ps[i2][j1-1]+ps[i1-1][j1-1] >= k) ;
//if(ps[i2][j2]-ps[i1-1][j2]-ps[i2][j1-1]+ps[i1-1][j1-1] >= k) cout << i << ' ' << j << '\n';
}
}
}
cout << ans;
return 0;
}
