#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
using f80 = long double;
using vi32 = vector<int>;
using vi64 = vector<i64>;
using vf80 = vector<f80>;
using vstr = vector<string>;
inline void yes() {
  cout << "Yes" << endl;
  exit(0);
}
inline void no() {
  cout << "No" << endl;
  exit(0);
}
inline i64 gcd(i64 a, i64 b) {
  if (min(a, b) == 0) return max(a, b);
  if (a % b == 0) return b;
  return gcd(b, a % b);
}
inline i64 lcm(i64 a, i64 b) {
  if (min(a, b) == 0) return max(a, b);
  return a / gcd(a, b) * b;
}
template <typename T>
class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template <typename T>
class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template <typename T>
inline void amax(T &x, T y) {
  x = max(x, y);
}
template <typename T>
inline void amin(T &x, T y) {
  x = min(x, y);
}
template <typename T>
inline T exp(T x, i64 n, T e = 1) {
  T r = e;
  while (n > 0) {
    if (n & 1) r *= x;
    x *= x;
    n >>= 1;
  }
  return r;
}
template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
  for (auto &x : v) is >> x;
  return is;
}
template <typename T>
ostream &operator<<(ostream &os, vector<T> &v) {
  for (int i = 0; i < int(v.size()); i++) {
    if (i) os << ' ';
    os << v[i];
  }
  return os;
}
void solve();
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout << fixed << setprecision(16);
  solve();
  return 0;
}
int dx[] = {-1, 0, 1, 0};
int dy[] = {0, -1, 0, 1};
void solve() {
  int h, w, k;
  cin >> h >> w >> k;
  vstr a(h);
  cin >> a;
  int sx, sy;
  for (int i = 0; i < int(h); i++)
    for (int j = 0; j < int(w); j++)
      if (a[i][j] == 'S') {
        sx = i, sy = j;
      }
  vector<vi32> dp(h, vi32(w, 1e9));
  using T = tuple<int, int, int, int>;
  queue<T> q;
  q.emplace(sx, sy, 1, k);
  while (((int)q.size())) {
    int x, y, c, s;
    tie(x, y, c, s) = q.front();
    q.pop();
    if (dp[x][y] != 1e9) continue;
    dp[x][y] = c;
    for (int i = 0; i < int(4); i++) {
      int nx = x + dx[i];
      int ny = y + dy[i];
      if (nx < 0 || nx >= h || ny < 0 || ny >= w) continue;
      if (a[nx][ny] == '#') continue;
      q.emplace(nx, ny, c, s - 1);
    }
  }
  for (int i = 0; i < int(h); i++)
    for (int j = 0; j < int(w); j++)
      if (dp[i][j] != 1e9) {
        for (int i = 0; i < int(4); i++) {
          int nx = i + dx[i];
          int ny = j + dy[i];
          if (nx < 0 || nx >= h || ny < 0 || ny >= w) continue;
          if (dp[nx][ny] != 1e9) continue;
          q.emplace(nx, ny, 2, k - 1);
        }
      }
  while (((int)q.size())) {
    int x, y, c, s;
    tie(x, y, c, s) = q.front();
    q.pop();
    if (dp[x][y] != 1e9) continue;
    dp[x][y] = c;
    if (s == 0) {
      c += 1;
      s = k;
    }
    for (int i = 0; i < int(4); i++) {
      int nx = x + dx[i];
      int ny = y + dy[i];
      if (nx < 0 || nx >= h || ny < 0 || ny >= w) continue;
      q.emplace(nx, ny, c, s - 1);
    }
  }
  int ans = 1e9;
  for (int i = 0; i < int(h); i++) {
    amin(ans, dp[i][0]);
    amin(ans, dp[i][w - 1]);
  }
  for (int j = 0; j < int(w); j++) {
    amin(ans, dp[0][j]);
    amin(ans, dp[h - 1][j]);
  }
  cout << ans << endl;
}
