#include <bits/stdc++.h>

using namespace std;

int main(int argc, const char *argv[]) {
  int n, m, k;
  cin >> n >> m >> k;
  vector<string> a(n);
  int sx, sy;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    for (int j = 0; j < m; j++) {
      if (a[i][j] == 'S') {
        sx = i, sy = j;
      }
    }
  }
  int dx[] = {-1, 0, 0, 1};
  int dy[] = {0, -1, 1, 0};
  queue<pair<int, int>> q;
  vector<vector<int>> dis(n, vector<int>(m, -1));
  dis[sx][sy] = 0;
  q.push({sx, sy});
  while (!q.empty()) {
    auto u = q.front();
    q.pop();
    int x = u.first, y = u.second;
    for (int i = 0; i < 4; i++) {
      int tx = x + dx[i], ty = y + dy[i];
      if (tx >= 0 && tx < n && ty >= 0 && ty < m && a[tx][ty] == '.' && dis[tx][ty] == -1) {
        dis[tx][ty] = dis[x][y] + 1;
        q.push({tx, ty});
      }
    }
  }
  int ans = 1e9;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (dis[i][j] != -1 && dis[i][j] <= k) {
        int minn = min(i, n - 1 - i);
        minn = min(minn, min(j, m - 1 - j));
        ans = min(ans, minn / k + (minn % k > 0));
      }
    }
  }
  cout << ans + 1 << endl;
  return 0;
}

