#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
#include <random>
#include <tuple>
#include <iomanip>
#include <cstring>

using namespace std;

typedef long long ll;
typedef vector<ll> vec;
typedef vector<vec> mat;
#define rep(i, n) for(ll i = 0; i < (n); i++)
#define revrep(i, n) for(ll i = (n-1); i >= 0; i--)
#define pb push_back
#define f first
#define s second
const ll INFL = 1LL << 60;//10^18 = 2^60
const int INF = 1 << 30;//10^9
ll MOD = 1000000007;
//ll MOD  = 998244353;
//vector<ll> dy = {0, 0, 1, -1, 1, 1, -1, -1, 0};
//vector<ll> dx = {1, -1, 0, 0, 1, -1, 1, -1, 0};
vector<ll> dy = {1, -1, 0, 0, 0};
vector<ll> dx = {0, 0, 1, -1, 0};

ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll pow_long(ll x, ll k){
  ll res = 1;
  while(k > 0){
    if(k % 2) res *= x;
    x *= x;
    k /= 2;
  }
  return res;
}
ll pow_mod(ll x, ll k){
  x %= MOD; x += MOD; x %= MOD;
  ll res = 1;
  while(k > 0){
    if(k % 2){
      res *= x; res %= MOD;
    }
    x *= x; x %= MOD;
    k /= 2;
  }
  return res;
}
ll inverse(ll x){return pow_mod(x, MOD - 2);};

//最大公約数
ll gcd(ll a, ll b){
    if(b == 0) return a;
    return gcd(b, a % b);
}

//最小公倍数
ll lcm(ll x, ll y){return x / gcd(x, y) * y;};

ll kai_mod(ll x){
  if(x == 0) return 1;
  return x * kai_mod(x-1) % MOD;
}

//コンビネーション
const int MAXcomb = 200010;
ll fac[MAXcomb], finv[MAXcomb], inv[MAXcomb];
//facはn!,finvは1/n!
//invは逆元
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;
    }
}
ll 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;
vector<vector<char>> mp(810, vector<char>(810));
int sy, sx;
int dist[810][810][1200];
typedef pair<pair<int, int>, pair<int, int>> P;


int dijkstra(){
  priority_queue<P, vector<P>, greater<P>> pque;
  //dist, rest, y, x
  dist[sy][sx][0] = 0;
  pque.push({{0, 0}, {sy, sx}});
  while(!pque.empty()){
    P p = pque.top();
    pque.pop();
    if(p.s.f == 0 || p.s.f == H-1){
      return (p.f.f-1) / K + 1;
    }
    if(p.s.s == 0 || p.s.s == W-1){
      return (p.f.f-1) / K + 1;
    }
    if((p.f.f / K + 1) * K < dist[p.s.f][p.s.s][p.f.s + K]){
      dist[p.s.f][p.s.s][p.f.s + K] = (p.f.f / K + 1) * K;
      pque.push({{dist[p.s.f][p.s.s][p.f.s + K], p.f.s + K}, {p.s.f, p.s.s}});
    }
    if(dist[p.s.f][p.s.s][p.f.s] < p.f.f) continue;
    rep(i, 5){
      int ny = p.s.f + dy[i];
      int nx = p.s.s + dx[i];
      if(mp[ny][nx] == '.'){
        if(p.f.f + 1 < dist[ny][nx][p.f.s]){
          dist[ny][nx][p.f.s] = p.f.f + 1;
          pque.push({{dist[ny][nx][p.f.s], p.f.s}, {ny, nx}});
        }
      }else{
        if(p.f.s == 0) continue;
        if(p.f.f + 1 < dist[ny][nx][p.f.s-1]){
          dist[ny][nx][p.f.s-1] = p.f.f + 1;
          pque.push({{dist[ny][nx][p.f.s-1], p.f.s-1}, {ny, nx}});
        }
      }
    }
  }
}

int main(){
  cin >> H >> W >> K;
  K = min(K, 410);
  rep(i, H){
    rep(j, W){
      cin >> mp[i][j];
      if(mp[i][j] == 'S'){
        sy = i;
        sx = j;
        mp[i][j] = '.';
      }
    }
  }
  rep(i, 810)rep(j, 810)rep(k, 1200) dist[i][j][k] = INF;
  cout << dijkstra() << endl;
}
