#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC target("tune=native")
#pragma GCC target("avx")
template <class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
T gcd(const T &a, const T &b) {
  return a < b ? gcd(b, a) : b ? gcd(b, a % b) : a;
}
template <class T>
T lcm(const T &a, const T &b) {
  return a / gcd(a, b) * b;
}
using ll = long signed long;
using ull = long unsigned long;
using cll = long long const;
using ld = long double;
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  ll h, w, k;
  cin >> h >> w >> k;
  vector<string> a(h);
  for (long long i = 0, i_len = (h); i < i_len; i++) cin >> a[i];
  ll si, sj;
  for (long long i = 0, i_len = (h); i < i_len; i++) {
    for (long long j = 0, j_len = (w); j < j_len; j++) {
      if (a[i][j] == 'S') {
        si = i;
        sj = j;
      }
    }
  }
  vector<vector<ll>> d(h, vector<ll>(w, 0x7FFFFFFF));
  using pl4 = pair<ll, ll>;
  using tl6 = tuple<ll, ll, ll>;
  auto comp = [&](tl6 i, tl6 j) -> bool { return get<2>(i) > get<2>(j); };
  priority_queue<tl6, vector<tl6>, decltype(comp)> q(comp);
  d[si][sj] = 0;
  q.push(tl6(si, sj, 0));
  vector<pl4> dx = {{-1, 0}, {+1, 0}, {0, -1}, {0, +1}};
  while (q.size()) {
    ll i = get<0>(q.top());
    ll j = get<1>(q.top());
    ll dij = get<2>(q.top());
    q.pop();
    if (dij != d[i][j]) continue;
    vector<pl4> kimbo;
    kimbo.reserve(4);
    for (pl4 &v : dx) {
      ll i2 = i + v.first;
      ll j2 = j + v.second;
      if (0 <= i2 && i2 < h && 0 <= j2 && j2 < w) {
        kimbo.emplace_back(i2, j2);
      }
    }
    for (pair<ll, ll> &u : kimbo) {
      ll i2 = u.first;
      ll j2 = u.second;
      ll cand;
      if ((a[i2][j2] == '#') == (a[i][j] == '#')) {
        cand = d[i][j] + 1;
      } else if (a[i][j] != '#') {
        cand = (d[i][j] / k + 1) * k;
      }
      if (chmin(d[i2][j2], cand)) {
        q.push(tl6(i2, j2, cand));
      }
    }
  }
  ll ans = 0x7FFFFFFF;
  for (long long i = 0, i_len = (h); i < i_len; i++) {
    chmin(ans, d[i][0]);
    chmin(ans, d[i][w - 1]);
  }
  for (long long j = 0, j_len = (w); j < j_len; j++) {
    chmin(ans, d[0][j]);
    chmin(ans, d[h - 1][j]);
  }
  cout << ans / k + 1 << endl;
}
