#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pint = pair<int, int>;
using pll = pair<ll, ll>;
using mint = map<int, int>;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
const char sp = ' ';
const char cmm = ',';
const int MOD = 1e9 + 7;
const int INF = 1e9;
const ll LINF = 1e18;
ll mod(ll a, ll b) { return (a % b + b) % b; }
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return a * b / gcd(a, b); }
void Yes() { cout << "Yes" << endl; }
void No() { cout << "No" << endl; }
void Judge(bool b) { b ? Yes() : No(); }
void YES() { cout << "YES" << endl; }
void NO() { cout << "NO" << endl; }
void JUDGE(bool b) { b ? YES() : NO(); }
ll powMod(ll b, ll e, ll m) {
  ll r = 1;
  while (e > 0) {
    if (e & 1) r = (r % m) * (b % m) % m;
    b = (b % m) * (b % m) % m;
    e >>= 1;
  }
  return r;
}
double distance(ll x1, ll y1, ll x2, ll y2) {
  return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
}
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 (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T>
void ppp(T n) {
  cout << n << endl;
}
template <typename T1, typename T2>
ostream& operator<<(ostream& s, const pair<T1, T2>& p) {
  return s << "(" << p.first << ", " << p.second << ")";
}
template <typename T>
ostream& operator<<(ostream& s, const vector<T>& v) {
  int len = v.size();
  s << '[';
  for (int i = 0; i < len; ++i) {
    s << v[i];
    if (i < len - 1) s << ", ";
  }
  s << ']';
  return s;
}
struct aaa {
  aaa() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15);
  };
} fastio;
vector<string> a(810);
vector<vector<bool>> done(810, vector<bool>(910, false));
int main() {
  int h, w, k;
  int sx, sy;
  cin >> h >> w >> k;
  queue<pint> q;
  for (int i = 0; i < (h); ++i) {
    cin >> a[i];
    for (int j = 0; j < (w); ++j) {
      if (a[i][j] == 'S') a[i][j] = '.', sx = j, sy = i;
    }
  }
  q.push(make_pair(sx, sy));
  done[sy][sx] = true;
  int mn = INF;
  while (!q.empty()) {
    int x, y;
    tie(x, y) = q.front();
    q.pop();
    chmin(mn, (x + k - 1) / k);
    chmin(mn, (w - x + k - 2) / k);
    chmin(mn, (y + k - 1) / k);
    chmin(mn, (h - y + k - 2) / k);
    for (int i = 0; i < (4); ++i) {
      int xx = x + dx[i];
      int yy = y + dy[i];
      if (xx < 0 or w <= xx or yy < 0 or h <= yy) continue;
      if (a[yy][xx] == '#') continue;
      if (!done[yy][xx]) q.push(make_pair(xx, yy)), done[yy][xx] = true;
    }
  }
  ppp(mn + 1);
  return 0;
}
