#include <bits/stdc++.h>
using namespace std;
int n, m, k;
char grid[1000][1000];
int steps[1000][1000];
int dx[4] = {0, 1, 0, -1};
int dy[4] = {1, 0, -1, 0};
queue<pair<int, int> > q;
int calc(int x, int y) {
  int xx = min(min(x, y), min(n - 1 - x, m - 1 - y));
  return (xx + k - 1) / k + 1;
}
int main() {
  cin >> n >> m >> k;
  pair<int, int> stt;
  memset(steps, 0x3f, sizeof(steps));
  for (int i = 0; i < n; i++) {
    scanf("%s", grid[i]);
    for (int j = 0; j < m; j++) {
      if (grid[i][j] == 'S') {
        stt = make_pair(i, j);
      }
    }
  }
  int res = 1e9;
  res = min(res, calc(stt.first, stt.second));
  q.push(stt);
  steps[stt.first][stt.second] = 0;
  while (!q.empty()) {
    stt = q.front();
    q.pop();
    res = min(res, calc(stt.first, stt.second));
    if (steps[stt.first][stt.second] >= k) break;
    for (int i = 0; i < 4; i++) {
      int nx = stt.first + dx[i], ny = stt.second + dy[i];
      if (nx >= 0 && nx < n && ny >= 0 && ny < m) {
        if (grid[nx][ny] != '#' && steps[nx][ny] >= 1e9) {
          steps[nx][ny] = steps[stt.first][stt.second] + 1;
          q.push(make_pair(nx, ny));
        }
      }
    }
  }
  cout << res << endl;
  return 0;
}
