#include <bits/stdc++.h>
using namespace std;
const int N = 1e3;
string s[N];
const int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
int dis[N][N], h, w, k;
void bfs(int sx, int sy) {
  memset(dis, -1, sizeof dis);
  dis[sx][sy] = 0;
  queue<pair<int, int> > q;
  q.push(pair<int, int>(sx, sy));
  while (q.size()) {
    int r = q.front().first, c = q.front().second;
    q.pop();
    for (int i = 0; i < 4; i++) {
      int nr = r + dx[i], nc = c + dy[i];
      if (nr >= 0 && nr < h && nc >= 0 && nc < w && dis[nr][nc] == -1 &&
          s[nr][nc] == '.') {
        dis[nr][nc] = dis[r][c] + 1;
        q.push(pair<int, int>(r, c));
      }
    }
  }
}
int main() {
  ios::sync_with_stdio(0);
  cout.tie(0);
  cin.tie(0);
  cin >> h >> w >> k;
  int sx, sy;
  for (int i = 0; i < h; i++) {
    cin >> s[i];
    for (int j = 0; j < w; j++)
      if (s[i][j] == 'S') sx = i, sy = j, s[i][j] = '.';
  }
  bfs(sx, sy);
  int ans = 1e9;
  for (int i = 0; i < h; i++)
    for (int j = 0; j < w; j++)
      if (dis[i][j] <= k && dis[i][j] != -1) {
        int t = min({i, j, h - i - 1, w - j - 1});
        ans = min(ans, (t + k - 1) / k + 1);
      }
  cout << ans << endl;
}
