#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define lld double
#define int ll
#define usaco(fname) freopen(#fname ".in","r",stdin);freopen(#fname ".out","w",stdout);
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { os << '{'; string sep; for (const T &x : v) os << sep << x, sep = ", "; return os << '}'; }
// const ll INF = 1e18;
const int INF = 1e9;
const int mod = 1e9+7;
const lld PI = acos(-1.0);
int di[] = {1, -1, 0, 0, 1, 1, -1, -1};
int dj[] = {0, 0, 1, -1, 1, -1, 1, -1};
#define debug(x) cout << #x << ": " << x << endl;
#define add(a, b) a += b, a %= mod
#define mul(a, b) ((a % mod) * (b % mod)) % mod
#define all(x) x.begin(),x.end()
void solve() {
int n,m,d,s;cin>>n>>m>>d>>s;
vector<vector<int>> pref(n, vector<int>(m));
vector<pair<int,int>> a;
for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) {
char c;cin>>c;
if (c == 'M') a.push_back({i, j});
else if (c == 'S') pref[i][j]++;
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (i-1 >= 0) pref[i][j] += pref[i-1][j];
if (j-1 >= 0) pref[i][j] += pref[i][j-1];
if (i-1 >= 0 && j-1 >= 0) pref[i][j] -= pref[i-1][j-1];
}
}
function<int(int, int, int, int)> get = [&](int i1, int j1, int i2, int j2) {
i1 = max(i1, 0ll);
j1 = max(j1, 0ll);
i2 = min(i2, n-1);
j2 = min(j2, m-1);
int sum = 0;
sum += pref[i2][j2];
if (j1-1 >= 0) sum -= pref[i2][j1-1];
if (i1-1 >= 0) sum -= pref[i1-1][j2];
if (i1-1 >= 0 && j1-1 >= 0) sum += pref[i1-1][j1-1];
return sum;
};
int ans = 0;
for (auto [i, j] : a) if (get(i-d, j-d, i+d, j+d) >= s) ans++;
cout << ans << endl;
}
int32_t main() {
ios_base::sync_with_stdio(0);cin.tie(0);
int t=1;
while(t--) solve();
return 0;
}
