#include <bits/stdc++.h>
using namespace std;
const long long INFL = 1LL << 60;
const int INF = 1 << 30;
long long MOD = 1000000007;
vector<long long> dy = {0, 0, 1, -1, 1, 1, -1, -1, 0};
vector<long long> dx = {1, -1, 0, 0, 1, -1, 1, -1, 0};
long long max(long long a, long long b) { return (a > b) ? a : b; }
long long min(long long a, long long b) { return (a < b) ? a : b; }
long long pow_long(long long x, long long k) {
  long long res = 1;
  while (k > 0) {
    if (k % 2) res *= x;
    x *= x;
    k /= 2;
  }
  return res;
}
long long pow_mod(long long x, long long k) {
  x %= MOD;
  x += MOD;
  x %= MOD;
  long long res = 1;
  while (k > 0) {
    if (k % 2) {
      res *= x;
      res %= MOD;
    }
    x *= x;
    x %= MOD;
    k /= 2;
  }
  return res;
}
long long inverse(long long x) { return pow_mod(x, MOD - 2); };
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long lcm(long long x, long long y) { return x / gcd(x, y) * y; };
long long kai_mod(long long x) {
  if (x == 0) return 1;
  return x * kai_mod(x - 1) % MOD;
}
const int MAXcomb = 200010;
long long fac[MAXcomb], finv[MAXcomb], inv[MAXcomb];
void COMinit() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAXcomb; i++) {
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}
long long comb(int n, int k) {
  if (n < k) return 0;
  if (n < 0 || k < 0) return 0;
  return fac[n] * finv[k] % MOD * finv[n - k] % MOD;
}
int H, W, K;
char mp[810][810];
int sy, sx;
bool can[810][810];
void bfs(long long y, long long x, long long rest) {
  if (rest == 0) return;
  for (long long i = 0; i < (4); i++) {
    long long ny = y + dy[i];
    long long nx = x + dx[i];
    if (ny < 0 || ny >= H || nx < 0 || nx >= W) continue;
    if (mp[ny][nx] == '#') continue;
    if (can[ny][nx]) continue;
    can[ny][nx] = 1;
    bfs(ny, nx, rest - 1);
  }
}
int main() {
  cin >> H >> W >> K;
  K = min(K, 410);
  for (long long i = 0; i < (H); i++) {
    for (long long j = 0; j < (W); j++) {
      cin >> mp[i][j];
      if (mp[i][j] == 'S') {
        sy = i;
        sx = j;
      }
    }
  }
  can[sy][sx] = 1;
  bfs(sy, sx, K);
  long long ans = INFL;
  for (long long i = 0; i < (H); i++)
    for (long long j = 0; j < (W); j++)
      if (can[i][j]) {
        if (i == 0 || i == H - 1 || j == 0 || j == W - 1)
          ans = 1;
        else {
          ans = min(ans, 1 + (i + K - 1) / K);
          ans = min(ans, 1 + (H - i - 1 + K - 1) / K);
          ans = min(ans, 1 + (j + K - 1) / K);
          ans = min(ans, 1 + (W - j - 1 + K - 1) / K);
        }
      }
  cout << ans << endl;
}
