#include <bits/stdc++.h>
#define MP make_pair
#define PB push_back
#define int long long
#define st first
#define nd second
#define rd third
#define FOR(i, a, b) for(int i =(a); i <=(b); ++i)
#define RE(i, n) FOR(i, 1, n)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define REP(i, n) for(int i = 0;i <(n); ++i)
#define VAR(v, i) __typeof(i) v=(i)
#define FORE(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
using namespace std;
template<typename TH> void _dbg(const char* sdbg, TH h) { cerr<<sdbg<<"="<<h<<"\n"; }
template<typename TH, typename... TA> void _dbg(const char* sdbg, TH h, TA... t) {
  while(*sdbg != ',')cerr<<*sdbg++; cerr<<"="<<h<<","; _dbg(sdbg+1, t...);
}
#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define debugv(x) {{cerr <<#x <<" = "; FORE(itt, (x)) cerr <<*itt <<", "; cerr <<"\n"; }}
#else
#define debug(...) (__VA_ARGS__)
#define debugv(x)
#define cerr if(0)cout
#endif
#define next ____next
#define prev ____prev
#define left ____left
#define hash ____hash
typedef long long ll;
typedef long double LD;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<pair<int, int> > VPII;
typedef vector<pair<ll, ll> > VPLL;

template<class C> void mini(C&a4, C b4){a4=min(a4, b4); }
template<class C> void maxi(C&a4, C b4){a4=max(a4, b4); }
template<class T1, class T2>
ostream& operator<< (ostream &out, pair<T1, T2> pair) { return out << "(" << pair.first << ", " << pair.second << ")";}
template<class A, class B, class C> struct Triple { A first; B second; C third;
  bool operator<(const Triple& t) const { if (st != t.st) return st < t.st; if (nd != t.nd) return nd < t.nd; return rd < t.rd; } };
template<class T> void ResizeVec(T&, vector<int>) {}
template<class T> void ResizeVec(vector<T>& vec, vector<int> sz) {
  vec.resize(sz[0]); sz.erase(sz.begin()); if (sz.empty()) { return; }
  for (T& v : vec) { ResizeVec(v, sz); }
}
typedef Triple<int, int, int> TIII;
template<class A, class B, class C>
ostream& operator<< (ostream &out, Triple<A, B, C> t) { return out << "(" << t.st << ", " << t.nd << ", " << t.rd << ")"; }
template<class T> ostream& operator<<(ostream& out, vector<T> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }

const int N = 8e2 + 5;
int is_exit[N][N];
int forb[N][N];
int dis[N][N];
int di[] = {1, -1, 0, 0};
int dj[] = {0, 0, 1, -1};
const int kDir = 4;
int vis[N][N];
int32_t main() {

  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(10);
  cerr << fixed << setprecision(10);
  cin.tie(0);
  //double beg_clock = 1.0 * clock() / CLOCKS_PER_SEC;
  
  int h, w, k;
  cin>>h>>w>>k;
  int si, sj;
  int nxt = 1;
  RE (i, h) {
    RE (j, w) {
      is_exit[i][j] = 1;
      char c;
      cin>>c;
      dis[i][j] = N * N - 5;
      if (c == 'S') {
        si = i;
        sj = j;
        dis[si][sj] = 0;
      }
      if (c == '#') {
        forb[i][j] = 1;
      }
    }
  }
  FOR (i, 2, h - 1) {
    FOR (j, 2, w - 1) {
      is_exit[i][j] = 0;
    }
  }
  int best = N * N;
  
  VPII que{{si, sj}}, nque;
  vis[si][sj] = 1;
  
  for (int ii = 0; ii < SZ(que); ii++) {
    auto p = que[ii];
    int d = dis[p.st][p.nd];
    if (is_exit[p.st][p.nd]) {
      if (dis[p.st][p.nd] <= k) {
        cout<<"1"<<endl;
        return 0;
      }
    } else {
      REP (dir, kDir) {
        int ni = p.st + di[dir];
        int nj = p.nd + dj[dir];
        if (forb[ni][nj]) { continue; }
        int ndis = d + 1;
        if (vis[ni][nj]) { continue; }
        vis[ni][nj] = 1;
        dis[ni][nj] = ndis;
        que.PB({ni, nj});
      }
    }
  }
  que.clear();
  RE (i, h) {
    RE (j, w) {
      if (dis[i][j] <= k) {
        dis[i][j] = 0;
        que.PB({i, j});
        vis[i][j] = 1;
      } else {
        dis[i][j] = N * N;
        vis[i][j] = 0;
      }
      
    }
  }
  for (int ii = 0; ii < SZ(que); ii++) {
    auto p = que[ii];
    int d = dis[p.st][p.nd];
    if (is_exit[p.st][p.nd]) {
      cout<<1 + (dis[p.st][p.nd] + k - 1) / k<<endl;
      return 0;
    } else {
      REP (dir, kDir) {
        int ni = p.st + di[dir];
        int nj = p.nd + dj[dir];
        int ndis = d + 1;
        if (vis[ni][nj]) { continue; }
        vis[ni][nj] = 1;
        dis[ni][nj] = ndis;
        que.PB({ni, nj});
      }
    }
  }
        
      
        
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  return 0;
}


Measured memory_bytes: 38504