#include <bits/stdc++.h>
#include <iomanip>
#define ll long long
#define int long long
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define str string
#define pii pair<int,int>
#define sz(x) x.size()
#define all(x) x.begin(), x.end()
#define vi vector<int>
#define mii map<int,int>
#define mll map<ll,ll>
#define yes cout<<"YES\n";
#define no cout<<"NO\n";
#define yess cout<<"Yes\n";
#define noo cout<<"No\n";
using namespace std;
#define maxn 1111111
#define mod 1000000007
void solve(){
int n,m,k,l;
cin>>n>>m>>k>>l;
int pp[n+3][m+3];
for(int i=0;i<=n;i++){
pp[i][0]=0;
}
for(int i=0;i<=m;i++){
pp[0][i]=0;
}
str s[n+3],d;
for(int i=1;i<=n;i++){
s[i]=" ";
cin>>d;
s[i]+=d;
for(int j=1;j<=m;j++){
pp[i][j]=(s[i][j]=='S');
pp[i][j]+=pp[i-1][j];
pp[i][j]+=pp[i][j-1];
pp[i][j]-=pp[i-1][j-1];
}
}
int ans=0;
for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
if(s[i][j]!='M'){
continue;
}
int l1,l2,r1,r2;
l1=max(1ll,i-k);
l2=min(n,i+k);
r1=max(1ll,j-k);
r2=min(m,j+k);
int c=pp[l2][r2]-pp[l1-1][r2]-pp[l2][r1-1]+pp[l1-1][r1-1];
if(c>=l){
ans++;
}
}
}
cout<<ans;
}
signed main(){
ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
//srand( time(0));
//freopen("sum.in", "r", stdin);
//freopen("sum.out", "w", stdout);
int tests=1;
//cin>>tests;
for(int i=1;i<=tests;i++){
//cout<<"Case "<<i<<": \n";
solve();
}
}
