#include <bits/stdc++.h>
using namespace std;
int n, m, d, k;
pair<int,int> g(pair<int,int> a, int d){
int x = a.first, y = a.second;
x = max(1, min(x+d, n));
y = max(1, min(y+d, m));
return {x, y};
}
int main(){
cin.tie(0) -> ios_base::sync_with_stdio(0);
cin >> n >> m >> d >> k;
vector<vector<int>> ps(n + 1, vector<int>(m + 1));
vector<pair<int,int>> v;
for(int i=1;i<=n;i++)
for(int j=1;j<=m;j++){
char a;
cin >> a;
if(a == 'M')
{
v.push_back({i, j});
}
else if(a == 'S')
{
ps[i][j]++;
}
}
for(int i=1;i<=n;i++)
{
for(int j=1;j<=m;j++)
{
ps[i][j] += ps[i-1][j] + ps[i][j-1] - ps[i-1][j-1];
}
}
int ans = 0;
for(auto i : v){
auto se = g(i, d);
auto fi = g(i, -d);
ans += ((long long)ps[se.first][se.second] - ps[se.first][fi.second-1] - ps[fi.first-1][se.second] + ps[fi.first-1][fi.second-1]) >= k;
}
cout << ans << '\n';
}
