#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define ent "\n"
const int maxn = 5e5 + 100;
const ll INF = (ll)1e18 + 100;
const int inf = 1e9 + 100;
const int MOD = 1e9 + 7;
const int maxl = 30;
const int P = 31;
int n, m, d, k;
vector<int> pref[maxn];
void test(){
cin >> n >> m >> d >> k;
pref[0] = vector<int>(m + 10, 0);
vector<pii> v, ad;
for(int i = 1; i <= n; i++){
pref[i] = pref[i-1];
for(int j = 1; j <= m; j++){
char c; cin >> c;
if(c == 'M') v.push_back({i, j});
else if(c == 'S') ad.push_back({i, j});
}
}
for(auto [i, j]: ad){
int a = max(1, i - d);
int x = min(n, i + d);
int b = max(1, j - d);
int y = min(m, j + d);
pref[a][b]++;
pref[a][y+1]--;
if(x < n){
pref[x+1][b]--;
pref[x+1][y+1]++;
}
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
pref[i][j] += pref[i-1][j];
}
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
pref[i][j] += pref[i][j-1];
}
}
int ans = 0;
for(auto [i, j]: v){
if(pref[i][j] >= k) ans++;
}
cout << ans << ent;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int t = 1; t = 1;
while(t--) test();
cout << ent;
}
