#include <bits/stdc++.h>
using namespace std;
const int N = 805, M = N * N;
int dx[4] = {0, 0, 1, -1}, dy[4] = {1, -1, 0, 0};
int n, m, k, i, j, a[N][N], h, t, qx[M], qy[M], ans;
char s[N];
int main() {
  scanf("%d%d%d", &n, &m, &k);
  for (i = 1; i <= n; i++) {
    scanf("%s", s + 1);
    for (j = 1; j <= m; j++) {
      if (s[j] == 'S') qx[1] = i, qy[1] = j;
      if (s[j] == '#') a[i][j] = 1;
    }
  }
  for (i = 1; i <= n; i++) a[i][0] = a[i][m + 1] = 1;
  for (i = 1; i <= m; i++) a[0][i] = a[n + 1][i] = 1;
  t = 1;
  a[qx[1]][qy[1]] = 1;
  ans = 1e9;
  for (; h != t;) {
    h++;
    int x = qx[h], y = qy[h];
    if (a[x][y] == k + 1) break;
    ans = min(ans, min(min(x - 1, n - x), min(y - 1, m - y)));
    for (i = 0; i < 4; i++) {
      int tx = x + dx[i], ty = y + dy[i];
      if (!a[tx][ty]) {
        a[tx][ty] = a[x][y] + 1;
        t++;
        qx[t] = tx;
        qy[t] = ty;
      }
    }
  }
  printf("%d", 1 + (ans + k - 1) / k);
}
