#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef long double ld;
typedef vector<ll> vi;
typedef pair<ll, ll> pi;
#define FOR(i, j, k) for (ll i = j; i < (ll) k; ++i)
#define FORD(i, j, k) for (ll i = j; i >= (ll) k; --i)
#define nl "\n"
#define sp " "
#define all(x) (x).begin(), (x).end()
#define sc second
#define fr first
#define pb push_back
void solve()
{
ll n, m, d, k;
cin >> n >> m >> d >> k;
vector<pi> mush;
ll sum[n + 1][m + 1] = {};
FOR(i, 1, n + 1) {
FOR(j, 1, m + 1) {
char c;
cin >> c;
ll cost = 0;
if(c == 'S')
cost = 1;
else if(c == 'M')
mush.pb({i, j});
sum[i][j] = sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1] + cost;
}
}
ll ans = 0;
for(auto [x, y] : mush) {
ll leftN = max(1LL, x - d);
ll rightN = min(x + d, n);
ll leftM = max(1LL, y - d);
ll rightM = min(y + d, m);
ll curr = sum[rightN][rightM] - sum[leftN - 1][rightM] - sum[rightN][leftM - 1] + sum[leftN - 1][leftM - 1];
if(curr >= k)
++ans;
}
cout << ans << nl;
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
ll t = 1;
// cin >> t;
while (t--)
{
solve();
}
}
