#include <bits/stdc++.h>
using namespace std;
const int N = 805;
int n, m, k;
char s[N][N];
int d[N][N], qx[N * N], qy[N * N];
int dx[4] = {0, 0, -1, 1};
int dy[4] = {-1, 1, 0, 0};
bool check(int x, int y) {
  return 1 <= x && x <= n && 1 <= y && y <= m && s[x][y] != '#';
}
int main() {
  cin >> n >> m >> k;
  for (int i = 1; i <= n; i++) scanf("%s", s[i] + 1);
  memset(d, 0, sizeof d);
  int sx, sy;
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m; j++)
      if (s[i][j] == 'S') sx = i, sy = j;
  int head = 0, tail = 0;
  tail++;
  qx[tail] = sx, qy[tail] = sy;
  d[sx][sy] = 1;
  while (head < tail) {
    head++;
    int x = qx[head], y = qy[head];
    if (d[x][y] == k) continue;
    for (int i = 0; i < 4; i++) {
      int nx = x + dx[i], ny = y + dy[i];
      if (!check(nx, ny) || d[nx][ny]) continue;
      d[nx][ny] = d[x][y] + 1;
      tail++;
      qx[tail] = nx, qy[tail] = ny;
    }
  }
  int ans = 23333;
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m; j++)
      if (s[i][j] != '#' && d[i][j]) {
        if (i == 1 || j == 1 || i == n || j == m)
          ans = 1;
        else {
          ans = min(ans, (i - 1 + k - 1) / k + 1);
          ans = min(ans, (j - 1 + k - 1) / k + 1);
          ans = min(ans, (n - i + k - 1) / k + 1);
          ans = min(ans, (m - j + k - 1) / k + 1);
        }
      }
  cout << ans;
  return 0;
}
