#include "bits/stdc++.h"
#define Rep(i,n) for(int i=0;i<(int)(n);i++)
#define For(i,n1,n2) for(int i=(int)(n1);i<(int)(n2);i++)
#define REP(i,n) for(ll i=0;i<(ll)(n);i++)
#define RREP(i,n) for(ll i=((ll)(n)-1);i>=0;i--)
#define FOR(i,n1,n2) for(ll i=(ll)(n1);i<(ll)(n2);i++)
#define RFOR(i,n1,n2) for(ll i=((ll)(n1)-1);i>=(ll)(n2);i--)
#define all(a)  (a).begin(),(a).end()
#define IOS std::cin.tie(0),std::ios::sync_with_stdio(false)

namespace idaten {

	using namespace std;
	using ll = int_fast64_t;
	using ull = uint_fast64_t;
	using P = std::pair<int64_t, int64_t>;
	template<typename T1, typename T2> inline bool chmin(T1& a, T2 b) { if (a > b) { a = b; return 1; }return 0; }
	template<typename T1, typename T2> inline bool chmax(T1& a, T2 b) { if (a < b) { a = b; return 1; }return 0; }
	template<class Type>struct is_vector : std::false_type {};
	template<class ValueType, class Alloc>struct is_vector<std::vector<ValueType, Alloc>> : std::true_type {};
	template <typename T> inline std::ostream& operator << (std::ostream& out, const std::vector<T>& v) {
		if (v.empty())return out;
		constexpr bool is_vector_v = is_vector<T>::value;
		if (is_vector_v)for (auto itr = v.begin(); itr != v.end();)out << (*itr), out << ((++itr != v.end()) ? "\n" : "");
		else for (auto itr = v.begin(); itr != v.end();)out << (*itr), out << ((++itr != v.end()) ? " " : "");
		return out;
	}
	inline void put() {}
	template<class T> inline void put(const T& first) { std::cout << first << "\n"; }
	template<class T, class... N> inline void put(const T& first, const N& ... rest) { std::cout << first << " "; put(rest...); }
	inline void putn() {}
	template<class T, class... N> inline void putn(const T& first, const N& ... rest) { std::cout << first << "\n"; putn(rest...); }

	template<typename T>
	struct edge {
		int to;
		T cost;
		edge(int t, T c) {
			to = t;
			cost = c;
		}
	};

	template<typename T>
	void dijkstra(int s, vector<vector<edge<T>>>& path, vector<T>& d) {
		using pi = pair<T, int>;
		priority_queue<pi, vector<pi>, greater<pi>> q;
		q.push(P(0, s));
		d[s] = 0;
		while (!q.empty()) {
			P p = q.top();
			q.pop();
			int v = p.second;
			if (d[v] < p.first)continue;
			REP(i, path[v].size()) {
				edge<T> e = path[v][i];
				if (d[e.to] > d[v] + e.cost) {
					d[e.to] = d[v] + e.cost;
					q.push(P(d[e.to], e.to));
				}
			}
		}
		return;
	}

	void solve() {
		IOS;
		int h, w, k;
		cin >> h >> w >> k;
		vector<string> a(h);
		REP(i, h) {
			cin >> a[i];
		}
		int s;
		REP(i, h) {
			REP(j, w) {
				if (a[i][j] == 'S') {
					s = i * w + j;
				}
			}
		}
		using ei=edge<int>;
		vector<vector<ei>> path(h* w);
		int dx[4] = { 0,0,1,-1 };
		int dy[4] = { 1,-1,0,0 };
		REP(i, h) {
			REP(j, w) {
				REP(o, 4) {
					int ny = i + dy[o];
					int nx = j + dx[o];
					if (0 <= ny && ny < h && 0 <= nx && nx < w) {
						int nex = ny * w + nx;
						int now = i * w + j;
						int cost = 0;
						if (a[ny][nx] == '#') {
							cost = k + 1;
						} else {
							cost = 1;
						}
						path[now].push_back(ei(nex, cost));
					}
				}
			}
		}
		vector<int> d(h* w, INT_MAX / 3);
		dijkstra(s, path, d);
		int res = INT_MAX;
		REP(i, h) {
			REP(j, w) {
				int now = i * w + j;
				if (d[now] <= k) {
					int dy = min(i, h - 1 - i);
					int dx = min(j, w - 1 - j);
					int d = min(dy, dx);
					int tmp = (d + k - 1) / k;
					chmin(res, tmp + 1);
				}
			}
		}
		put(res);
	}

} // namespace idaten

int main() {
	idaten::solve();
	return 0;
}

Measured memory_bytes: 50680