#include <bits/stdc++.h>
using namespace std;
const double PI = 2 * acos(0.0);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());
const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";
template <class T0, class T1>
inline ostream &operator<<(ostream &out, pair<T0, T1> &a) {
  return out << "{" << a.first << ", " << a.second << "}";
}
template <class T0, class T1>
inline istream &operator>>(istream &in, pair<T0, T1> &a) {
  return in >> a.first >> a.second;
}
template <class T0, class T1, class T2>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2> &a) {
  return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a)
             << "}";
}
template <class T0, class T1, class T2, class T3>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2, T3> &a) {
  return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a)
             << ", " << get<3>(a) << "}";
}
template <class T>
inline ostream &operator<<(ostream &out, vector<T> &a) {
  out << "[";
  for (int i = 0; i < int(a.size()); ++i)
    out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
  return out;
}
void smain();
signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cout << setprecision(12) << fixed;
  smain();
  return 0;
}
const int N = 888;
int n, m;
string mat[N];
int dist[N][N];
vector<int> di = {0, 0, -1, 1};
vector<int> dj = {-1, 1, 0, 0};
const int oo = 1e9 + 10;
void smain() {
  for (int i = 0; i < int(N); ++i) {
    for (int j = 0; j < int(N); ++j) {
      dist[i][j] = -1;
    }
  }
  cin >> n >> m;
  int k;
  cin >> k;
  for (int i = 0; i < int(n); ++i) {
    cin >> mat[i];
  }
  pair<int, int> st;
  for (int i = 0; i < int(n); ++i) {
    for (int j = 0; j < int(m); ++j) {
      if (mat[i][j] == 'S') {
        st = {i, j};
        if (i == 0 || i + 1 == n || j == 0 || j + 1 == m) {
          cout << "0";
          return;
        }
      }
    }
  }
  queue<pair<int, int> > q;
  q.push(st);
  dist[st.first][st.second] = 0;
  while (!q.empty()) {
    pair<int, int> v = q.front();
    q.pop();
    for (int dir = 0; dir < int(di.size()); ++dir) {
      int i = v.first + di[dir];
      int j = v.second + dj[dir];
      if (i >= 0 && i < n && j >= 0 && j < m && mat[i][j] != '#' &&
          dist[i][j] == -1) {
        dist[i][j] = dist[v.first][v.second] + 1;
        q.push({i, j});
      }
    }
  }
  int ans = oo;
  for (int i = 0; i < int(n); ++i) {
    for (int j = 0; j < int(m); ++j) {
      if (dist[i][j] != -1 && dist[i][j] <= k) {
        ans = min(
            ans, (1 + (min(min(i, n - i - 1), min(j, n - j - 1)) + k - 1) / k));
      }
    }
  }
  cout << ans;
}
