#define _CRT_SECURE_NO_WARNINGS
#define _SCL_SECURE_NO_WARNINGS
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <utility>
#include <algorithm>
#include <functional>
#include <cmath>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <iomanip>
#include <sstream>
#include <bitset>
#include <limits>
#include <numeric>
#include <valarray>
#include <fstream>

using namespace std;
typedef unsigned int uint;
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<LL, LL> PP;
#define REP(i,a,n) for(LL i = (a); i < (LL)(n); ++i)
#define REM(i,a,n) for(LL i = ((n) - 1); i >= (a); --i)
#define FLOAT fixed << setprecision(16)
#define SPEEDUP {cin.tie(NULL); ios::sync_with_stdio(false);}
const int INF = 0x3FFFFFFF;
const LL INFLL = 0x3FFFFFFF3FFFFFFF;
const double INFD = 1.0e+308;
const string INFSTR = "\x7f";
const double EPS = 1.0e-9;

void YesNo(bool b) { cout << (b ? "Yes" : "No") << endl; }
void YESNO(bool b) { cout << (b ? "YES" : "NO") << endl; }
template <class T, class U>
istream& operator>>(istream& ist, pair<T, U>& right) { return ist >> right.first >> right.second; }
template <class T, class U>
ostream& operator<<(ostream& ost, const pair<T, U>& right) { return ost << right.first << ' ' << right.second; }
template <class T, class TCompatible, size_t N>
void Fill(T(&dest)[N], const TCompatible& val) { fill(dest, dest + N, val); }
template <class T, class TCompatible, size_t M, size_t N>
void Fill(T(&dest)[M][N], const TCompatible& val) { for (int i = 0; i < M; ++i) Fill(dest[i], val); }
template<class T>
T Compare(T left, T right) { return left > right ? 1 : (left < right ? -1 : 0); }
istream& Ignore(istream& ist) { string s; ist >> s; return ist; }
bool Inside(int i, int j, int h, int w) { return i >= 0 && i < h && j >= 0 && j < w; }
// all_of
// partial_sum, adjacent_difference

#ifdef ONLY_MY_ENVIR
#include "IntMod.h"
#include "Union_Find.h"
#include "Graph.h"
#include "Range.h"
#include "Global.h"
#include "Flow_Solver.h"
#include "Tree.h"
#include "Suffix_Array.h"
#include "Geometry.h"
#include "Matrix.h"
#endif

#ifdef __GNUC__
typedef __int128 LLL;
istream& operator>> (istream& ist, __int128& val) { LL tmp;  ist >> tmp; val = tmp; return ist; }
ostream& operator<< (ostream& ost, __int128 val) { LL tmp = val; ost << tmp; return ost; }
#endif

#if 1234567891
#include <array>
#include <random>
#include <unordered_set>
#include <unordered_map>
template<typename T>
using PriorityQ = priority_queue<T, vector<T>, greater<T> >;	// コスト小を優先
#endif


int H, W, K;
string S[800];
int si, sj;

int Dist(int i,int j) {
	return min({ i, j, H - i - 1, W - j - 1 });
}

int di[] = { 0,1,0,-1 };
int dj[] = { 1,0,-1,0 };

int dist[800][800];
int BFS(int si, int sj) {
	int ret = Dist(si, sj);

	queue<PP> Q;
	Q.push(PP(si, sj));
	Fill(dist, INF);
	dist[si][sj] = 0;
	while (!Q.empty()) {
		PP p = Q.front(); Q.pop();
		int i = p.first;
		int j = p.second;
		if (S[i][j] == '#') continue;
		if (dist[i][j] > K) continue;
		ret = min(ret, Dist(i, j));

		REP(k, 0, 4) {
			int p = i + di[k];
			int q = j + dj[k];
			if (!Inside(p, q, H, W)) continue;
			if (dist[p][q] != INF) continue;
			dist[p][q] = dist[i][j] + 1;
			Q.push(PP(p, q));
		}
	}
	return ret;
}

int main() {
	cin >> H >> W >> K;
	REP(i, 0, H) {
		cin >> S[i];
		REP(j, 0, W) {
			if (S[i][j] == 'S') {
				si = i;
				sj = j;
			}
		}
	}

	int dist = BFS(si, sj);
	cout << 1 + (dist + K - 1) / K << endl;
	return 0;
}


Measured memory_bytes: 3712