#include <bits/stdc++.h>
using namespace std;
#define name "IO"
#define int long long
const int inf = 1e18 + 7;
const int maxn = 5e5 + 5;
int r, c, d, k;
vector<vector<char>> grid;
struct Fenw
{
vector<vector<int>> tree;
int n, m;
Fenw(int n_, int m_)
{
n = n_, m = m_;
tree.resize(n + 5, vector<int>(m + 5, 0));
}
void update(int i, int j, int val)
{
for(int u = i; u <= n; u += u & -u)
{
for(int v = j; v <= m; v += v & -v)
tree[u][v] += val;
}
}
int preSum(int i, int j)
{
int ans = 0;
for(int u = i; u > 0; u -= u &-u)
{
for(int v = j; v > 0; v -= v & -v)
ans += tree[u][v];
}
return ans;
}
int query(int i, int j, int u, int v)
{
return preSum(u, v) - preSum(i - 1, v) - preSum(u, j - 1) + preSum(i - 1, j - 1);
}
};
void solve()
{
cin >> r >> c >> d >> k;
grid.resize(r + 5, vector<char>(c + 5));
vector<pair<int,int>> nam, tuoi;
for(int i = 1; i <= r; i++)
{
for(int j = 1; j <= c; j++)
{
cin >> grid[i][j];
if(grid[i][j] == 'M') nam.push_back({i, j});
if(grid[i][j] == 'S') tuoi.push_back({i, j});
}
}
Fenw bit(r, c);
for(auto [x, y] : tuoi)
{
int i, j, u, v;
i = max(1ll, x - d), j = max(1ll, y - d);
u = min(r, x + d), v = min(c, y + d);
bit.update(i, j, 1);
bit.update(i, v + 1, -1);
bit.update(u + 1, j, -1);
bit.update(u + 1, v + 1, 1);
}
int res = 0;
for(auto [x, y] : nam)
{
int num = bit.preSum(x, y);
res += (num >= k);
}
cout << res << "\n";
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
clock_t start = clock();
int t = 1;
while(t--) solve();
std::cerr << "Time: " << clock() - start << "ms\n";
return 0;
}
