#include <bits/stdc++.h>
using namespace std;
int Q[1010000][2], head, tail, D[810][810];
int n, m, K, sx, sy;
char p[810][810];
void Ins(int x, int y, int d) {
  if (D[x][y] <= d || p[x][y] != '.') {
    return;
  }
  D[x][y] = d;
  tail++;
  Q[tail][0] = x;
  Q[tail][1] = y;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int i, j, x, y;
  cin >> n >> m >> K;
  for (i = 1; i <= n; i++) {
    scanf("%s", p[i] + 1);
    for (j = 1; j <= m; j++) {
      if (p[i][j] == 'S') sx = i, sy = j, p[i][j] = '.';
      D[i][j] = 1e9;
    }
  }
  Ins(sx, sy, 0);
  while (head < tail) {
    head++;
    x = Q[head][0], y = Q[head][1];
    Ins(x + 1, y, D[x][y] + 1);
    Ins(x, y + 1, D[x][y] + 1);
    Ins(x - 1, y, D[x][y] + 1);
    Ins(x, y - 1, D[x][y] + 1);
  }
  int res = 1e9;
  for (i = 1; i <= n; i++) {
    for (j = 1; j <= m; j++) {
      if (D[i][j] <= K) {
        res = min(res,
                  1 + (min(min(i - 1, n - i), min(j - 1, m - j)) + K - 1) / K);
      }
    }
  }
  cout << res;
  return 0;
}
