#include<bits/stdc++.h>
using namespace std;
#define foru(i,a,b) for(int i=(a); i<=(b); ++i)
#define ford(i,a,b) for(int i=(a); i>=(b); --i)
#define rep(i,a) for(int i=0; i<(a); ++i)
#define sz(a) (int)(a).size()
#define all(a) (a).begin(),(a).end()
#define bit(s,i) (((s)>>(i))&1)
#define ii pair<int,int>
#define vi vector<int>
#define vii vector<ii>
#define fi first
#define se second
#define ll long long
#define eb emplace_back
#define pb push_back
#define __builtin_popcount __builtin_popcountll
#define _ << " " <<
template <class X, class Y> bool maxi(X &x, Y y){return x<y?x=y,true:false;}
template <class X, class Y> bool mini(X &x, Y y){return x>y?x=y,true:false;}
const int N=500500;
int r,c,d,k;
string s[N];
vector<int> sum[N];
void solve(){
cin>>r>>c>>d>>k;
foru(i,1,r){
cin>>s[i];
s[i]=" "+s[i];
}
foru(i,0,r+1) sum[i].resize(c+2,0);
foru(i,1,r){
foru(j,1,c){
if(s[i][j]=='S'){
int x=max(1,i-d), y=max(1,j-d), u=min(r,i+d), v=min(c,j+d);
sum[x][y]++;
sum[x][v+1]--;
sum[u+1][y]--;
sum[u+1][v+1]++;
}
}
}
int res=0;
foru(i,1,r) foru(j,1,c){
sum[i][j]+=sum[i-1][j]+sum[i][j-1]-sum[i-1][j-1];
if(s[i][j]=='M') res+=sum[i][j]>=k;
}
cout<<res<<'\n';
}
int32_t main(){
#define task "test"
if(fopen(task".inp", "r")){
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
cin.tie(0)->sync_with_stdio(0);
int tc=1; //cin>>tc;
foru(i,1,tc){
solve();
}
}
