#include<bits/stdc++.h>
using namespace std;
#define int long long
#define inf 5e18
#define nl '\n'
inline void solve(){
int n, m, d, k;
cin>>n>>m>>d>>k;
int pre[n+1][m+1];
for(int i=0; i<n; i++) pre[i][0] = 0;
for(int i=0; i<m; i++) pre[0][i] = 0;
vector<pair<int,int>> v;
for(int i=1; i<=n; i++){
for(int j=1; j<=m; j++){
char c;
cin>>c;
pre[i][j] = pre[i-1][j] + pre[i][j-1] - pre[i-1][j-1] + (c == 'S');
if(c == 'M') v.push_back({i, j});
}
}
int ans = 0;
for(auto [i, j] : v){
int a = max(i-d, 1ll), b = max(j-d, 1ll), x = min(i+d, n), y = min(j+d, m);
ans += pre[x][y] - pre[x][b-1] - pre[a-1][y] + pre[a-1][b-1] >= k;
}
cout<<ans;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);cout.tie(NULL);
int t = 1;
//cin>>t;
while(t--) solve();
return 0;
}
