#include <bits/stdc++.h>
using namespace std;
long long modpow(long long x, long long y,
                 long long m = (long long)(1000000007)) {
  long long res = 1;
  while (y) {
    if (y % 2) {
      res *= x;
      res %= m;
    }
    x = x * x % (long long)(1000000007);
    y /= 2;
  }
  return res;
}
long long mypow(long long x, long long y) {
  long long res = 1;
  while (y) {
    if (y % 2) {
      res *= x;
    }
    x = x * x;
    y /= 2;
  }
  return res;
}
bool prime(long long x) {
  for (long long i = 2; i * i <= x; i++) {
    if (!(x % i)) {
      return false;
    }
  }
  return true;
}
inline long long gcd(long long x, long long y) {
  if (!y) {
    return x;
  }
  return gcd(y, x % y);
}
long long keta(long long x) {
  long long ans = 0;
  while (x) {
    x /= 10;
    ans++;
  }
  return ans;
}
long long ketasum(long long x) {
  long long ans = 0;
  while (x) {
    ans += x % 10;
    x /= 10;
  }
  return ans;
}
inline long long lcm(long long x, long long y) {
  long long ans = x / gcd(x, y) * y;
  return ans;
}
long long twobeki(long long x) {
  long long ans = 0;
  while (1) {
    if (!(x & 1)) {
      ans++;
      x /= 2;
    } else {
      break;
    }
  }
  return ans;
}
template <class T, class U>
inline bool chmax(T& lhs, const U& rhs) {
  if (lhs < rhs) {
    lhs = rhs;
    return 1;
  }
  return 0;
}
template <class T, class U>
inline bool chmin(T& lhs, const U& rhs) {
  if (lhs > rhs) {
    lhs = rhs;
    return 1;
  }
  return 0;
}
void Yes() { cout << "Yes" << endl; }
void No() { cout << "No" << endl; }
void YES() { cout << "YES" << endl; }
void NO() { cout << "NO" << endl; }
class modInt {
  long long value, modulo;

 public:
  modInt() : value(0), modulo((long long)(1000000007)) { value = 0; }
  template <typename T>
  modInt(T value = 0, long long modulo = (long long)(1000000007))
      : value(value), modulo(modulo) {
    if (value < 0) {
      value = -value;
      value %= modulo;
      value = -value;
      value += modulo;
    }
    this->value = value % modulo;
  }
  inline operator long long() const { return value; }
  inline modInt& operator+=(modInt x) {
    value += x.value;
    if (value >= modulo) value -= modulo;
    return *this;
  }
  inline modInt& operator++() {
    if (value == modulo - 1)
      value = 0;
    else
      value++;
    return *this;
  }
  inline modInt& operator-() const { return modInt(0) -= *this; }
  inline modInt& operator-=(modInt x) {
    value -= x.value;
    if (value < 0) value += modulo;
    return *this;
  }
  inline modInt& operator--() {
    if (value == 0)
      value = modulo - 1;
    else
      value--;
    return *this;
  }
  inline modInt& operator*=(modInt x) {
    value = value * x.value % modulo;
    return *this;
  }
  inline modInt& operator/=(modInt x) { return operator*=(x.inv()); }
  inline modInt inv() { return modpow(*this, modulo - 2); }
  template <typename T>
  modInt operator+(T x) {
    return modInt(*this) += x;
  }
  template <typename T>
  modInt& operator+=(T x) {
    return operator+=(modInt(x, modulo));
  }
  template <typename T>
  modInt operator-(T x) {
    return modInt(*this) -= x;
  }
  template <typename T>
  modInt& operator-=(T x) {
    return operator-=(modInt(x, modulo));
  }
  template <typename T>
  modInt operator*(T x) {
    return modInt(*this) *= x;
  }
  template <typename T>
  modInt& operator*=(T x) {
    return operator*=(modInt(x, modulo));
  }
  template <typename T>
  modInt operator/(T x) {
    return modInt(*this) /= x;
  }
  template <typename T>
  modInt& operator/=(T x) {
    return operator/=(modInt(x, modulo));
  }
};
istream& operator>>(istream& ist, modInt& x) {
  long long a;
  ist >> a;
  x = a;
  return ist;
}
class Union_Find {
  vector<long long> par;
  vector<long long> rankmy;
  vector<long long> ookisa;

 public:
  Union_Find(long long size) {
    par = vector<long long>(size);
    rankmy = vector<long long>(size);
    ookisa = vector<long long>(size);
    for (long long i = 0; i < size; i++) {
      par[i] = i;
      ookisa[i] = 1;
    }
  }
  long long find(long long x) {
    if (par[x] == x) {
      return x;
    }
    return par[x] = find(par[x]);
  }
  void unite(long long x, long long y) {
    x = find(x);
    y = find(y);
    if (x == y) {
      return;
    }
    if (rankmy[x] < rankmy[y]) {
      par[x] = y;
      ookisa[y] += ookisa[x];
      ookisa[x] = 0;
    } else {
      par[y] = x;
      ookisa[x] += ookisa[y];
      ookisa[y] = 0;
      if (rankmy[x] == rankmy[y]) {
        rankmy[x]++;
      }
    }
  }
  long long size(long long i) {
    i = find(i);
    return ookisa[i];
  }
  bool same(long long x, long long y) { return find(x) == find(y); }
};
long long h, w, k, d, cnt, ans;
string a[1004];
bool went[1004][1004];
void solve(long long x, long long y, long long now) {
  if (a[x][y] == '#') return;
  if (went[x][y]) return;
  if (now < 0) return;
  went[x][y] = 1;
  if (x) solve(x - 1, y, now - 1);
  if (y) solve(x, y - 1, now - 1);
  if (x < h - 1) solve(x + 1, y, now - 1);
  if (y < w - 1) solve(x, y + 1, now - 1);
}
signed main() {
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  cin >> h >> w >> k;
  for (long long i = 0; i < h; i++) {
    cin >> a[i];
    for (long long j = 0; j < w; j++) {
      if (a[i][j] == 'S') {
        if (!i || !j || i == h - 1 || j == w - 1) {
          cout << 0 << endl;
          return 0;
        }
      }
    }
  }
  for (long long i = 0; i < h; i++) {
    for (long long j = 0; j < w; j++) {
      if (a[i][j] == 'S') {
        solve(i, j, k);
      }
    }
  }
  cnt = (long long)(3e18);
  for (long long i = 0; i < h; i++) {
    for (long long j = 0; j < w; j++) {
      if (went[i][j]) {
        chmin(cnt, min({i, j, h - i - 1, w - j - 1}));
      }
    }
  }
  ans = max(0ll, (cnt + k - 1) / k) + 1;
  cout << ans << endl;
}
