#include <algorithm>
#include <bitset>
#include <cmath>
#include <complex>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <regex>
#include <set>
#include <stack>
#include <string>
#include <vector>

const int MOD = 1e9 + 7;
const int iINF = 2147483647 / 2;
const long long int llINF = 9223372036854775807 / 2;

using namespace std;
using ll = long long int;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
using vvvl = vector<vector<vector<ll>>>;

typedef pair<ll, ll> pll;
bool paircomp(const pll &a, const pll &b) {
  if (a.first == b.first)
    return a.second < b.second;
  return a.first < b.first;
}

#define REP(i, n) for (ll i = 0; i < (n); i++)
#define RREP(i, n) for (ll i = (n)-1; i >= 0; i--)
#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define AUTO(i, m) for (auto &i : m)
#define ALL(a) (a).begin(), (a).end()
#define MAX(vec) *std::max_element(vec.begin(), vec.end())
#define MIN(vec) *std::min_element(vec.begin(), vec.end())
#define ARGMAX(vec)                                                            \
  std::distance(vec.begin(), std::max_element(vec.begin(), vec.end()))
#define ARGMIN(vec)                                                            \
  std::distance(vec.begin(), std::min_element(vec.begin(), vec.end()))
#define REV(T) greater<T>()
#define PQ(T) priority_queue<T, vector<T>, greater<T>>
#define VVL(a, b, c) vector<vector<ll>>(a, vector<ll>(b, c))
#define VV(T, a, b, c) vector<vector<T>>(a, vector<T>(b, c))
#define VVVL(a, b, c, d)                                                       \
  vector<vector<vector<ll>>>(a, vector<vector<ll>>(b, vector<ll>(c, d)))
#define SP(a) setprecision(a)
#define SQRT(a) sqrt((long double)(a))
#define DPOW(a, b) pow((long double)(a), (long double)(b))
#define UNIQUE(vec)                                                            \
  do {                                                                         \
    sort(ALL((vec)));                                                          \
    (vec).erase(std::unique(ALL((vec))), (vec).end());                         \
  } while (0)

ll POW(ll n, ll m) {
  if (m == 0) {
    return 1;
  } else if (m % 2 == 0) {
    ll tmp = POW(n, m / 2);
    return (tmp * tmp);
  } else {
    return (n * POW(n, m - 1));
  }
}

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ll H, W, K;
  cin >> H >> W >> K;
  vvl A = VVL(H, W, 0);
  pll start;
  REP(i, H) REP(j, W) {
    char s;
    cin >> s;
    if (s == '#')
      A[i][j] = 1;
    else if (s == 'S')
      start = make_pair(i, j);
  }
  // 次に移動する分の部屋の鍵は開けられるので、扉の制約があるのは1回目だけ！！
  ll ans = llINF;
  queue<pair<ll, pll>> Q;
  Q.push(make_pair(0, start));
  while (!Q.empty()) {
    auto po = Q.front();
    Q.pop();
    ll count = po.first;
    if (po.second.first < 0 || po.second.first >= H || po.second.second < 0 ||
        po.second.second >= W || A[po.second.first][po.second.second] == 1)
      continue;
    ans = min(ans, min(min(po.second.first, po.second.second),
                       min(H - 1 - po.second.first, W - 1 - po.second.second)));
    A[po.second.first][po.second.second] = 1; //一度行ったところはもう見ない
    if (count < K) {
      Q.push(make_pair(count + 1,
                       make_pair(po.second.first + 1, po.second.second)));
      Q.push(make_pair(count + 1,
                       make_pair(po.second.first - 1, po.second.second)));
      Q.push(make_pair(count + 1,
                       make_pair(po.second.first, po.second.second + 1)));
      Q.push(make_pair(count + 1,
                       make_pair(po.second.first, po.second.second - 1)));
    }
  }
  if (ans == 0)
    cout << 1 << endl;
  else {
    cout << 1 + ceil((long double)ans / K) << endl;
  }
  return 0;
}


Measured memory_bytes: 5376