#include <iostream>
#include <iomanip>
#include <sstream>
#include <vector>
#include <string>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
#include <functional>
#include <iterator>
#include <limits>
#include <numeric>
#include <utility>
#include <type_traits>
#include <cmath>
#include <cassert>
#include <cstdio>

using namespace std;
using namespace placeholders;

using LL = long long;
using ULL = unsigned long long;
using VI = vector< int >;
using VVI = vector< vector< int > >;
using VS = vector< string >;
using ISS = istringstream;
using OSS = ostringstream;
using PII = pair< int, int >;
using VPII = vector< pair< int, int > >;
template < typename T = int > using VT = vector< T >;
template < typename T = int > using VVT = vector< vector< T > >;
template < typename T = int > using LIM = numeric_limits< T >;

template < typename T > inline istream& operator>>( istream &s, vector< T > &v ){ for ( T &t : v ) { s >> t; } return s; }
template < typename T > inline ostream& operator<<( ostream &s, const vector< T > &v ){ for ( int i = 0; i < int( v.size() ); ++i ){ s << ( " " + !i ) << v[i]; } return s; }

template < typename T > struct getv_fmt;
template <> struct getv_fmt<       int >{ static constexpr const char *fmt = "%d"; };
template <> struct getv_fmt< long long >{ static constexpr const char *fmt = "%lld"; };
template < typename T > void getv( std::vector< T > &v ){ for_each( begin( v ), end( v ), []( T &a ){ scanf( getv_fmt< T >::fmt, &a ); } ); };

template < typename T > inline T fromString( const string &s ) { T res; istringstream iss( s ); iss >> res; return res; }
template < typename T > inline string toString( const T &a ) { ostringstream oss; oss << a; return oss.str(); }

#define NUMBERED( name, number ) NUMBERED2( name, number )
#define NUMBERED2( name, number ) name ## _ ## number
#define REP1( n ) REP2( NUMBERED( REP_COUNTER, __LINE__ ), n )
#define REP2( i, n ) REP3( i, 0, n )
#define REP3( i, m, n ) for ( int i = ( int )( m ); i < ( int )( n ); ++i )
#define GET_REP( a, b, c, F, ... ) F
#define REP( ... ) GET_REP( __VA_ARGS__, REP3, REP2, REP1 )( __VA_ARGS__ )
#define FOR( e, c ) for ( auto &&e : c )
#define ALL( c ) begin( c ), end( c )
#define AALL( a ) ( remove_all_extents< decltype( a ) >::type * )a, ( remove_all_extents< decltype( a ) >::type * )a + sizeof( a ) / sizeof( remove_all_extents< decltype( a ) >::type )
#define DRANGE( c, p ) begin( c ), begin( c ) + ( p ), end( c )

#define SZ( v ) ( (int)( v ).size() )
#define EXIST( c, e ) ( ( c ).find( e ) != ( c ).end() )

template < typename T > inline bool chmin( T &a, const T &b ){ if ( b < a ) { a = b; return true; } return false; }
template < typename T > inline bool chmax( T &a, const T &b ){ if ( a < b ) { a = b; return true; } return false; }

#define PB push_back
#define EM emplace
#define EB emplace_back
#define BI back_inserter

#define MP make_pair
#define fst first
#define snd second

#define DUMP( x ) cerr << #x << " = " << ( x ) << endl

constexpr int INF = LIM<>::max() / 2;

constexpr int dy[] = { 0, 1, 0, -1 };
constexpr int dx[] = { 1, 0, -1, 0 };

int main()
{
	cin.tie( 0 );
	ios::sync_with_stdio( false );
	cout << setprecision( 12 ) << fixed;

	int H, W, K;
	cin >> H >> W >> K;

	VS board( H );
	cin >> board;

	int sy, sx;
	REP( i, H )
	{
		REP( j, W )
		{
			if ( board[i][j] == 'S' )
			{
				tie( sy, sx ) = tie( i, j );
				board[i][j] = '.';
			}
		}
	}

	const auto inside = [&]( const int y, const int x ){ return 0 <= y && y < H && 0 <= x && x < W; };

	VVI distances1( H, VI( W, INF ) );
	distances1[ sy ][ sx ] = 0;

	queue< PII > que;
	que.EM( sy, sx );

	int res = INF;

	while ( !que.empty() )
	{
		const int y = que.front().fst;
		const int x = que.front().snd;
		que.pop();
		
		{
			const int ry = min( y, H - 1 - y );
			const int rx = min( x, W - 1 - x );
			chmin( res, 1 + ( ry + K - 1 ) / K );
			chmin( res, 1 + ( rx + K - 1 ) / K );
		}

		if ( K <= distances1[y][x] )
		{
			continue;
		}

		REP( d, 4 )
		{
			const int ny = y + dy[d];
			const int nx = x + dx[d];

			if ( !inside( ny, nx ) || board[ ny ][ nx ] == '#' || distances1[ ny ][ nx ] != INF )
			{
				continue;
			}

			distances1[ ny ][ nx ] = distances1[y][x] + 1;
			que.EM( ny, nx );
		}
	}

	cout << res << endl;

	return 0;
}


Measured memory_bytes: 3456