/*
Author: Nguyen Chi Thanh - High School for the Gifted - VNU.HCM (i2528)
*/
#include <bits/stdc++.h>
using namespace std;
/* START OF TEMPALTE */
// #define int long long
#define ll long long
#define ull unsigned long long
#define ld long double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define __builtin_popcount __builtin_popcountll
#define all(x) (x).begin(), (x).end()
#define BIT(x, i) (((x) >> (i)) & 1)
#define MASK(x) (1ll << (x))
#define SZ(a) ((int32_t)a.size())
#define debug(a, l, r) {for (int _i = (l); _i <= (r); ++_i) cout << (a)[_i] << ' '; cout << '\n';}
template<class X, class Y>
bool minimize(X &x, const Y &y) {
if (x > y) {
x = y;
return true;
} else return false;
}
template<class X, class Y>
bool maximize(X &x, const Y &y) {
if (x < y) {
x = y;
return true;
} else return false;
}
/* END OF TEMPALTE */
void solve() {
int n, m, d, k;
cin >> n >> m >> d >> k;
vector<pii> sprinkers_pos, mushrooms_pos;
for (int i = 1; i <= n; ++i) {
string s; cin >> s;
s = ' ' + s;
for (int j = 1; j <= m; ++j) {
if (s[j] == 'M') mushrooms_pos.push_back({i, j});
else if (s[j] == 'S') sprinkers_pos.push_back({i, j});
}
}
vector<vector<int>> grid(n + 5, vector<int>(m + 5, 0));
auto updateRect = [&] (int r1, int c1, int r2, int c2) {
if (r1 > r2 || c1 > c2) return;
grid[r1][c1] += 1;
grid[r1][c2 + 1] -= 1;
grid[r2 + 1][c1] -= 1;
grid[r2 + 1][c2 + 1] += 1;
};
for (auto u : sprinkers_pos) {
int r1 = max(1, u.fi - d);
int c1 = max(1, u.se - d);
int r2 = min(n, u.fi + d);
int c2 = min(m, u.se + d);
updateRect(r1, c1, r2, c2);
}
for (int i = 1; i <= n; ++i)
for (int j = 1; j <= m; ++j)
grid[i][j] = (grid[i - 1][j] + grid[i][j - 1] - grid[i - 1][j - 1] + grid[i][j]);
int res = 0;
for (auto u : mushrooms_pos)
if (grid[u.fi][u.se] >= k) res += 1;
cout << res;
}
signed main() {
#ifdef NCTHANH
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
solve();
return 0;
}
