#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) {
  if (a < b) gcd(b, a);
  long long r;
  while ((r = a % b)) {
    a = b;
    b = r;
  }
  return b;
}
long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
long long modpow(long long a, long long n, long long mod) {
  long long res = 1;
  while (n > 0) {
    if (n & 1) res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}
long long modinv(long long a, long long mod) {
  long long b = mod, u = 1, v = 0;
  while (b) {
    long long t = a / b;
    a -= t * b;
    swap(a, b);
    u -= t * v;
    swap(u, v);
  }
  u %= mod;
  if (u < 0) u += mod;
  return u;
}
namespace NTT {
const int MOD = 998244353;
const long long PR = 3;
void trans(vector<long long> &v, bool inv = false) {
  int n = (int)v.size();
  for (int i = 0, j = 1; j < n - 1; j++) {
    for (int k = n >> 1; k > (i ^= k); k >>= 1)
      ;
    if (i > j) swap(v[i], v[j]);
  }
  for (int t = 2; t <= n; t <<= 1) {
    long long bw = modpow(PR, (MOD - 1) / t, MOD);
    if (inv) bw = modinv(bw, MOD);
    for (int i = 0; i < n; i += t) {
      long long w = 1;
      for (int j = 0; j < t / 2; ++j) {
        int j1 = i + j, j2 = i + j + t / 2;
        long long c1 = v[j1], c2 = v[j2] * w % MOD;
        v[j1] = c1 + c2;
        v[j2] = c1 - c2 + MOD;
        while (v[j1] >= MOD) v[j1] -= MOD;
        while (v[j2] >= MOD) v[j2] -= MOD;
        w = w * bw % MOD;
      }
    }
  }
  if (inv) {
    long long inv_n = modinv(n, MOD);
    for (int i = 0; i < n; ++i) v[i] = v[i] * inv_n % MOD;
  }
}
vector<long long> mult(vector<long long> A, vector<long long> B) {
  int size_a = 1;
  while (size_a < A.size()) size_a <<= 1;
  int size_b = 1;
  while (size_b < B.size()) size_b <<= 1;
  int size_fft = max(size_a, size_b) << 1;
  vector<long long> cA(size_fft, 0), cB(size_fft, 0), cC(size_fft, 0);
  for (int i = 0; i < A.size(); ++i) cA[i] = A[i];
  for (int i = 0; i < B.size(); ++i) cB[i] = B[i];
  trans(cA);
  trans(cB);
  for (int i = 0; i < size_fft; ++i) cC[i] = cA[i] * cB[i] % MOD;
  trans(cC, true);
  vector<long long> res((int)A.size() + (int)B.size() - 1);
  for (int i = 0; i < res.size(); ++i) res[i] = cC[i];
  return res;
}
};  // namespace NTT
signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int h, w, k;
  cin >> h >> w >> k;
  int x, y;
  string a[805];
  for (int i = 0; i < h; i++) {
    cin >> a[i];
    for (int j = 0; j < w; j++) {
      if (a[i][j] == 'S') {
        x = i;
        y = j;
      }
    }
  }
  queue<pair<int, pair<int, int> > > que;
  que.push(pair<int, pair<int, int> >(0, pair<int, int>(x, y)));
  int ans = INT_MAX;
  while (!que.empty()) {
    pair<int, int> now = que.front().second;
    int tmp = que.front().first;
    que.pop();
    if (now.first < 0 || now.first >= h || now.second < 0 || now.second >= w ||
        a[now.first][now.second] == '#')
      continue;
    int xh = min(h - 1 - now.first, now.first);
    int yh = min(w - 1 - now.second, now.second);
    ans = 1 + min(ans, min(xh / k + min(1, xh % k), yh / k + min(1, yh % k)));
    a[now.first][now.second] = '#';
    if (tmp < k) {
      que.push(pair<int, pair<int, int> >(
          tmp + 1, pair<int, int>(now.first + 1, now.second)));
      que.push(pair<int, pair<int, int> >(
          tmp + 1, pair<int, int>(now.first - 1, now.second)));
      que.push(pair<int, pair<int, int> >(
          tmp + 1, pair<int, int>(now.first, now.second + 1)));
      que.push(pair<int, pair<int, int> >(
          tmp + 1, pair<int, int>(now.first, now.second - 1)));
    }
  }
  cout << ans;
}
