#include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>
#include <numeric>
#include <sstream>
#include <iostream>
#include <iomanip>
#define _USE_MATH_DEFINES
#include <cmath>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <cfloat>
#include <cmath>
#include <ctime>
#include <cstdio>
#include <cassert>
using namespace std;

#define EPS 1e-12
#define ull unsigned long long
#define ll long long
#define VI vector<ll>
#define PII pair<ll, ll> 
#define VVI vector<vector<ll> >
#define REP(i,n) for(int i=0,_n=(n);(i)<(int)_n;++i)
#define RANGE(i,a,b) for(int i=(int)a,_b=(int)(b);(i)<_b;++i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define ALL(c) (c).begin(), (c).end()
#define ALLR(c) (c).rbegin(), (c).rend()
#define PB push_back
#define MP(a, b) make_pair(a, b)
#define POPCOUNT __builtin_popcount
#define POPCOUNTLL __builtin_popcountll
#define CLEAR(table, v) memset(table, v, sizeof(table));
#define PRINT1(table, D0) REP(d0, D0) cout<<table[d0]<<" "; cout<<"\n";
#define PRINT2(table, D0, D1) REP(d0, D0) { REP(d1, D1) cout<<table[d0][d1]<<" "; cout<<"\n"; }
#define PRINT3(table, D0, D1, D2) REP(d0, D0) { REP(d1, D1) { REP(d2, D2) cout<<table[d0][d1][d2]<<" "; cout<<"\n"; } cout<<"\n"; }
#define UNIFORM_DOUBLE(a, b) (((b-a)*(double)rand()/RAND_MAX)+a) // [a, b) 
#define UNIFORM_LL(a, b) (ll)UNIFORM_DOUBLE(a, b) // [a, b) 
#define IN(v, lo, hi) ((lo)<=(v) && (v)<(hi))
#define DD(v) cout<<#v<<": "<<v<<endl
template <typename T0, typename T1> std::ostream& operator<<(std::ostream& os, const map<T0, T1>& v) { for( typename map<T0, T1>::const_iterator p = v.begin(); p!=v.end(); p++ ){os << p->first << ": " << p->second << " ";} return os; }
template <typename T0, typename T1> std::ostream& operator<<(std::ostream& os, const pair<T0, T1>& v) { os << v.first << ": " << v.second << " "; return os; }
template <typename T> std::ostream& operator<<(std::ostream& os, const vector<T>& v) { for( int i = 0; i < (int)v.size(); i++ ) { os << v[i] << " "; } return os; }
template <typename T> std::ostream& operator<<(std::ostream& os, const vector<vector<T> >& v) { for( int i = 0; i < (int)v.size(); i++ ) { os << v[i] << endl; } return os; }
template <typename T> std::ostream& operator<<(std::ostream& os, const set<T>& v) { vector<T> tmp(v.begin(), v.end()); os << tmp; return os; }
template <typename T> std::ostream& operator<<(std::ostream& os, const deque<T>& v) { vector<T> tmp(v.begin(), v.end()); os << tmp; return os; }

#define MOD 1000000007LL
#define INF (1LL<<60)

int main() {
	//ios::sync_with_stdio(false);
	ll W,H,K;
	string s;
	while(cin>>H>>W>>K) {
		vector<string> w(H);
		deque<PII> q;
		VVI p(H, VI(W, INF));
		REP(y, H) {
			cin>>w[y];
			REP(x, W) if(w[y][x]=='S') {
				q.push_back(MP(x, y));
				p[y][x] = 0;
			}
		}
		int dx[] = {0,0,1,-1};
		int dy[] = {1,-1,0,0};
		while(q.size()) {
			PII c = q.front(); q.pop_front();
			ll x = c.first;
			ll y = c.second;
			REP(d, 4) {
				ll nx = x+dx[d];
				ll ny = y+dy[d];
				ll ncost = p[y][x]+1;
				if(IN(nx, 0, W) && IN(ny, 0, H) && w[ny][nx]=='.' && p[ny][nx] > ncost) {
					p[ny][nx] = ncost;
					q.push_back(MP(nx, ny));
				}
			}
		}
//		DD(p);
		ll ans = INF;
		REP(y, H) REP(x, W) if(p[y][x]<=K) {
			ans = min(ans, 1+(x +K-1)/K);
			ans = min(ans, 1+(W-1-x +K-1)/K);
			ans = min(ans, 1+(y +K-1)/K);
			ans = min(ans, 1+(H-1-y +K-1)/K);
		}
		cout<<ans<<endl;
	}
	
	return 0;
}


Measured memory_bytes: 7160