//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")
#include<bits/stdc++.h>
using namespace std;
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define sz(a) (int)a.size()
#define s second
#define f first
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
vector<pii> rid = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
vector<pii> dir = {{-1, -1}, {-1, 1}, {1, -1}, {1, 1}};
const int N = 2e5 + 1, mod = 998244353;
const ll inf = 1e9;
double eps = 1e-15;
bool flg = 0;
void slv() {
int n, m, d, k;
cin >> n >> m >> d >> k;
int p[n + 1][m + 1];
memset(p, 0, sizeof(p));
char c[n + 1][m + 1];
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
cin >> c[i][j];
p[i][j] = p[i - 1][j] + p[i][j - 1] - p[i - 1][j - 1];
if (c[i][j] == 'S') p[i][j]++;
}
}
int ans = 0;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (c[i][j] == 'M') {
int x = min(n, i + d), y = min(m, j + d);
int a = max(1, i - d), b = max(1, j - d);
int v = p[x][y] - p[x][b - 1];
v += p[a - 1][b - 1] - p[a - 1][y];
if (v >= k)
ans++;
}
}
}
cout << ans;
}
main() {
//freopen("rsq.in", "r", stdin);
//freopen("rsq.out", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);
int tp = 1;
if (flg) cin >> tp;
while (tp--) {
slv();
}
}
//wenomechainsama
