// By ObeliX
#include <bits/stdc++.h>
#pragma GCC target( "sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#include <unordered_map>
#include <cstddef>
#include <cassert>
#include <bitset>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <cmath>
#include <queue>
#include <map>
#include <set>
using namespace std;
const long long N = 1e6 + 5;
const long long MOD = 1e7 + 7;
const long long inf = 1e18;
long long n , m , d , k;
int main(){
//freopen( "cinema.in" , "r" , stdin );
//freopen( "cinema.out" , "w" , stdout );
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> m >> d >> k;
char c[n+5][m+5];
long long pref[n+5][m+5];
for ( int i = 0 ; i <= n + 1 ; i++ ) {
for ( int j = 0 ; j <= m + 1 ; j++ ) {
c[i][j] = '.';
pref[i][j] = 0;
}
}
long long cnt1 = 0 , cnt2 = 0;
for ( int i = 1 ; i <= n ; i++ ) {
for ( int j = 1 ; j <= m ; j++ ) {
cin >> c[i][j];
pref[i][j] += pref[i-1][j];
pref[i][j] += pref[i][j-1];
pref[i][j] -= pref[i-1][j-1];
if ( c[i][j] == 'S' ) {
pref[i][j]++;
}
}
}
long long ans = 0;
for ( int i = 1 ; i <= n ; i++ ) {
for ( int j = 1 ; j <= m ; j++ ) {
if ( c[i][j] == 'M' ) {
long long x2 = min( n , i + d ) , y2 = min( m , j + d );
long long x1 = max( 0ll , i - d - 1 ) , y1 = max( 0ll , j - d - 1 );
long long x = pref[x2][y2] - ( pref[x2][y1] + pref[x1][y2] ) + pref[x1][y1];
if ( x >= k ) {
ans++;
}
}
}
}
cout << ans;
}
