// includes
#include <bits/stdc++.h>

// macros
#define ll long long int
#define pb emplace_back
#define mk make_pair
#define pq priority_queue
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define irep(itr, st) for(auto itr = (st).begin(); itr != (st).end(); ++itr)
#define irrep(itr, st) for(auto itr = (st).rbegin(); itr != (st).rend(); ++itr)
#define vrep(v, i) for(int i = 0; i < (v).size(); i++)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define FI first
#define SE second
#define dump(a, n) for(int i = 0; i < n; i++)cout << a[i] << "\n "[i + 1 != n];
#define dump2(a, n, m) for(int i = 0; i < n; i++)for(int j = 0; j < m; j++)cout << a[i][j] << "\n "[j + 1 != m];
#define bit(n) (1LL<<(n))
#define INT(n) int n; cin >> n;
#define LL(n) ll n; cin >> n;
#define DOUBLE(n) double n; cin >> n;
using namespace std;

//  types
typedef pair<int, int> P;
typedef pair<ll, int> Pl;
typedef pair<ll, ll> Pll;
typedef pair<double, double> Pd;
typedef complex<double> cd;
 
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1e9 + 7;
const int dx[4] = {-1, 0, 1, 0};
const int dy[4] = {0, -1, 0, 1};

// solve
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}
template <typename T> ostream &operator<<(ostream &os, const vector<T>& vec){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){os << p.first << " " << p.second; return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}

int h, w, k;
string s[801];

struct state{
  int i, j, k, m, r;
  state(){}
  state(int i, int j, int k, int m, int r): i(i), j(j), k(k), m(m), r(r){}
  bool operator<(const state &R) const{
    if(m != R.m)return m > R.m;
    if(k != R.k)return k > R.k;
    return r < R.r;
  }
};

int dis[801][801];

int main(int argc, char const* argv[])
{
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(20);
  cin >> h >> w >> k;
  rep(i, h)cin >> s[i];
  int sx = 0, sy = 0;
  rep(i, h)rep(j, w)if(s[i][j] == 'S')sx = i, sy = j;
  priority_queue<state> pq;
  rep(i, h)rep(j, w)dis[i][j] = inf;
  dis[sx][sy] = 1;
  pq.push(state(sx, sy, 0, 1, 0));
  while(!pq.empty()){
    auto p = pq.top(); pq.pop();
    if(dis[p.i][p.j] < p.m)continue;
    rep(l, 4){
      int nx = p.i + dx[l];
      int ny = p.j + dy[l];
      if(nx >= 0 && nx < h && ny >= 0 && ny < w){
        if(s[nx][ny] == '#'){
          state s = state(nx, ny, p.k + 1, p.m, p.r - 1);
          if(s.r < 0){
            s.r = k - 1;
            s.k = 1;
            s.m++;
          }
          if(s.k > k){
            s.k = 1;
            s.m++;
            s.r += k;
          }
          if(dis[nx][ny] > s.m){
            dis[nx][ny] = s.m;
            pq.push(s);
          }
        }else{
          state s = state(nx, ny, p.k + 1, p.m, p.r);
          if(s.k > k){
            s.k = 1;
            s.m++;
            s.r += k;
          }
          if(dis[nx][ny] > s.m){
            dis[nx][ny] = s.m;
            pq.push(s);
          }
        }
      }
    }
  }
  int res = inf;
  rep(i, h){
    chmin(res, dis[i][0]);
    chmin(res, dis[i][w-1]);
  }
  rep(j, w){
    chmin(res, dis[0][j]);
    chmin(res, dis[h-1][j]);
  }
  cout << res << endl;
  return 0;
}


Measured memory_bytes: 8820