/*
no more temmy :(
*/
#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
// #include<icecream.hpp>
// using namespace icecream;
#define ll long long
#define int ll
#define ld long double
#define y1 cheza
// mt19937 rng(1983413);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<class T> using ordered_set = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
const int N=5e5+100;
const int M=1e6;
const int B=317;
const int mod=998244353;
const int INF=1e18;
const int lg=64;
const int dx[]={1,-1,0,0};
const int dy[]={0,0,1,-1};
const double eps=1e-9;
int n,m,d,k;
vector<vector<int>>pref;
int get(int x1,int y1,int x2,int y2){
return pref[x2][y2]-pref[x2][y1-1]-pref[x1-1][y2]+pref[x1-1][y1-1];
}
void test(){
cin>>n>>m>>d>>k;
pref=vector<vector<int>>(n+1,vector<int>(m+1,0));
vector<pair<int,int>>a,b;
for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
pref[i][j]=pref[i-1][j]+pref[i][j-1]-pref[i-1][j-1];
char x;
cin>>x;
if(x=='M'){
a.push_back({i,j});
}
if(x=='S'){
b.push_back({i,j});
pref[i][j]++;
}
}
}
if(b.size()<k){
cout<<0<<'\n';
return;
}
int ans=0;
for(auto [x,y]:a){
int res=get(max(x-d,1ll),max(y-d,1ll),min(x+d,n),min(y+d,m));
if(res>=k){
ans++;
}
}
cout<<ans<<'\n';
}
/*
*/
signed main(){
// ic.prefix("debug->| ");
// freopen("input.txt","r",stdin);
// freopen("output.txt","w",stdout);
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
// cout.tie(nullptr);
long long t2=1;
// cin>>t2;
for(int i=1;i<=t2;i++){
test();
}
return 0;
}
