#include <bits/stdc++.h>
#define sts(v) svble_sort(v.BE, v.E)
#define Rsts(v) svble_sort(v.rBE, v.rE)
#define rev(v) reverse(v.BE, v.E)
#define BE begin()
#define rBE rbegin()
#define E end()
#define rE rend()
#define pb push_back
#define ppb pop_back()
#define pf push_front
#define ppf pop_front()
#define F first
#define S second
using namespace std;
using ll = long long;
const int MAXN = 1e5 + 1;
const int MOD = 1e9 + 7;
int n, m, D, K;
pair<int, int> new_cord(int a, int b){
if(a < 1 or a > n + D or b < 1 or b > m + D)return {0, 0};
else return {a, b};
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n >> m >> D >> K;
vector<pair<int,int>> mushroom;
vector<vector<int>> v(n + D + 10, vector<int> (m + D + 10));
for(int i = 1; i <= n; i++)
for(int j = 1; j <= m; j++){
char c; cin >> c;
if(c == 'S')v[i][j] = 1;
else if(c == 'M')mushroom.pb({i, j});
}
for(int i = 1; i <= n + D; i++)
for(int j = 1; j <= m + D; j++)
v[i][j] = v[i - 1][j] + v[i][j - 1] - v[i - 1][j - 1] + v[i][j];
int cnt = 0;
for(auto &i : mushroom){
pair<int, int> cor1 = new_cord(i.F + D, i.S + D), cor2 = new_cord(i.F - D - 1, i.S - D - 1),
cor3 = new_cord(i.F + D, i.S - D - 1), cor4 = new_cord(i.F - D - 1, i.S + D);
if(K <= v[cor1.F][cor1.S] + v[cor2.F][cor2.S] - v[cor3.F][cor3.S] - v[cor4.F][cor4.S])cnt++;
}
cout << cnt << '\n';
return 0;
}
