#include <iostream>
#include <iomanip>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <stack>
#include <queue>
#include <bitset>
#include <numeric>
#include <cassert>
#ifdef DEBUG
#include "./Lib/debug.hpp"
#else
#define dump(...)
template<class T>inline auto d_val(T a, T b) { return a; }
#endif

/* (=＾o＾=) */
#define int ll

/* macro */
#define FOR(i, b, e) for(ll i = (ll)(b); i < (ll)(e); ++i)
#define RFOR(i, b, e) for(ll i = (ll)(e-1); i >= (ll)(b); --i)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) RFOR(i, 0, n)
#define REPC(x,c) for(const auto& x:(c))
#define REPI2(it,b,e) for(auto it = (b); it != (e); ++it)
#define REPI(it,c) REPI2(it, (c).begin(), (c).end())
#define RREPI(it,c) REPI2(it, (c).rbegin(), (c).rend())
#define REPI_ERACE2(it, b, e) for(auto it = (b); it != (e);)
#define REPI_ERACE(it, c) REPI_ERACE2(it, (c).begin(), (c).end())
#define ALL(x) (x).begin(),(x).end()
#define cauto const auto&
/* macro func */
#define SORT(x) do{sort(ALL(x));}while(false)
#define RSORT(x) do{sort((x).rbegin(),(x).rend());}while(false)
#define UNIQUE(v) do{v.erase( unique(v.begin(), v.end()), v.end() );}while(false)
#define MAX(x,y) do{x = std::max(x,y);}while(false)
#define MIN(x,y) do{x = std::min(x,y);}while(false)
#define BR do{cout<<"\n";}while(false)

/* type define */
using ll = long long;
using PAIR = std::pair<ll, ll>;
using VS = std::vector<std::string>;
using VL = std::vector<long long>;
using VVL = std::vector<VL>;
using VVVL = std::vector<VVL>;
using VD = std::vector<double>;
template<class T>
using V = std::vector<T>;

/* using std */
using std::cout;
constexpr char endl = '\n';
using std::cin;
using std::sort;
using std::pair;
using std::string;
using std::stack;
using std::queue;
using std::vector;
using std::list;
using std::map;
using std::unordered_map;
using std::multimap;
using std::unordered_multimap;
using std::set;
using std::unordered_set;
using std::unordered_multiset;
using std::multiset;
using std::bitset;
using std::priority_queue;

/* constant value */
constexpr ll MOD = 1000000007;
//constexpr ll MOD = 998244353;

/* Initial processing  */
struct Preprocessing { Preprocessing() { std::cin.tie(0); std::ios::sync_with_stdio(0); }; }_Preprocessing;

/* Remove the source of the bug */
signed pow(signed, signed) { assert(false); return -1; }

/* define hash */
namespace std { template <>	class hash<std::pair<ll, ll>> { public:	size_t operator()(const std::pair<ll, ll>& x) const { return hash<ll>()(1000000000 * x.first + x.second); } }; }

/* input */
template<class T> std::istream& operator >> (std::istream& is, vector<T>& vec) { for (T& x : vec) is >> x; return is; }

//=============================================================================================


signed main() {
	ll h, w, k;
	cin >> h >> w >> k;
	VS mp(h);
	cin >> mp;

	PAIR s;
	REP(i, h)REP(j, w) {
		if (mp[i][j] == 'S') { s = {i,j}; }
	}

	using type = pair<ll, PAIR>;
	VVL cost(h, VL(w, 1e9));
	priority_queue<type, V<type>, std::greater<type>> q;
	q.emplace(0, s);
	cost[s.first][s.second] = 0;

	auto go = [&](ll y, ll x, ll c) {
		if (y < 0 || y >= h || x < 0 || x >= w) { return; }
		if (mp[y][x] == '#') { return; }
		if (cost[y][x] < 1e8) { return; }
		if (c == k + 1) { return; }
		q.emplace(c, PAIR{y,x});
		cost[y][x] = c;
	};

	while (!q.empty()) {
		ll cost = q.top().first;
		PAIR from = q.top().second;
		q.pop();
		go(from.first + 1, from.second, cost + 1);
		go(from.first - 1, from.second, cost + 1);
		go(from.first, from.second + 1, cost + 1);
		go(from.first, from.second - 1, cost + 1);
	}
	dump(cost);
	ll ans = 1e9;
	REP(i, h)REP(j, w) {
		if (cost[i][j] > 1e8) { continue; }
		MIN(ans, 1 + ((h - i - 1) + k - 1) / k);
		MIN(ans, 1 + ((w - j - 1) + k - 1) / k);
		MIN(ans, 1 + (i + k - 1) / k);
		MIN(ans, 1 + (j + k - 1) / k);
	}	
	cout << ans << endl;
}

Measured memory_bytes: 6016