#include <bits/stdc++.h>
#include <iomanip>
#define ll long long
#define int long long
#define pb push_back
#define F first
#define mpk make_pair
#define S second
#define st string
#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 yes cout<<"Yes\n";
#define no cout<<"No\n";
#define lf else if
using namespace std;
void why(){
ll n,m,d,k,ans=0;
cin>>n>>m>>d>>k;
ll pp[n+7][m+7];
for(ll i=0;i<=n;i++){
pp[i][0]=0;
}
for(ll i=0;i<=m;i++){
pp[0][i]=0;
}
st v[n+7],s;
for(ll i=1;i<=n;i++)
{
v[i]=" ";
cin>>s;
v[i]+=s;
for(ll j=1;j<=m;j++)
{
pp[i][j]=(v[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];
}
}
for(ll i=1;i<=n;i++)
{
for(ll j=1;j<=m;j++)
{
if(v[i][j]!='M')continue;
ll l1=max(i-d,1ll);
ll l2=min(i+d,n);
ll r1=max(j-d,1ll);
ll r2=min(j+d,m);
ll an=pp[l2][r2]-pp[l1-1][r2]-pp[l2][r1-1]+pp[l1-1][r1-1];
if(an>=k)
{
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);
//ll tests=1;
//cin>>tests;
//for(ll i=1;i<=tests;i++)
//{
//cout<<"Case "<<i<<":\n";
why();
//}
}
