#include <bits/stdc++.h>
using namespace std;
int main()
{
#ifdef ONPC
freopen ("input.txt", "r", stdin);
#endif // ONPC
#ifndef ONPC
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#endif // ONPC
int n, m, r, need;
cin >> n >> m >> r >> need;
vector<pair<int, int>> mus, spr;
for (int i = 0; i < n; i++)
{
string s;
cin >> s;
assert((int) s.size() == m);
for (int j = 0; j < m; j++)
{
char ch = s[j];
if (ch == '.')
{
continue;
}
if (ch == 'S')
{
spr.push_back({i, j + 1});
continue;
}
if (ch == 'M')
{
mus.push_back({i, j + 1});
continue;
}
assert(0);
}
}
int sol = 0;
sort(mus.begin(), mus.end());
sort(spr.begin(), spr.end());
int p1 = 0, p2 = 0;
for (auto &it : mus)
{
while (p1 < (int) spr.size() && spr[p1].first <= it.first + r)
{
p1++;
}
while (p2 < (int) spr.size() && spr[p2].first < it.first - r)
{
p2++;
}
int cnt = 0;
int low = max(1, it.second - r), high = min(m, it.second + r);
for (int j = p2; j < p1; j++)
{
if (low <= spr[j].second && spr[j].second <= high)
{
cnt++;
}
}
sol += (cnt >= need);
}
cout << sol << "\n";
}
