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Artifact a89ac69a75cbec949f1a4eee0f1fabc2c6ef3314


#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <functional>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
#include <cassert>
#include <cstring>
using namespace std;
typedef long long LL;
typedef complex<double> CMP;

class KnightsTour { public:
	int visitedPositions(vector <string> board) 
	{
		// sentinels
		for(int yy=0; yy<board.size(); ++yy)
			board[yy] = "**"+board[yy]+"**";
		board.push_back( string(board[0].size(),'*') );
		board.push_back( string(board[0].size(),'*') );
		board.insert( board.begin(), string(board[0].size(),'*') );
		board.insert( board.begin(), string(board[0].size(),'*') );

		// starting point
		int y, x;
		for(int yy=0; yy<board.size(); ++yy)
		for(int xx=0; xx<board[yy].size(); ++xx)
			if(board[yy][xx]=='K')
				y=yy, x=xx;

		int n = 1;
		while( step(board,y,x) )
			++n;
		return n;
	}

	bool step(vector<string>& B, int& Y, int& X)
	{
		int dy[]={-2,-2,-1,-1,+1,+1,+2,+2};
		int dx[]={-1,+1,-2,+2,-2,+2,-1,+1};
		int minAn = 9999;
		for(int i=0; i<8; ++i)
			if( B[Y+dy[i]][X+dx[i]] == '.' )
				minAn = min(minAn, an(B,Y+dy[i],X+dx[i]));
		if( minAn == 9999 )
			return false;
		for(int i=0; i<8; ++i)
			if( B[Y+dy[i]][X+dx[i]] == '.' )
				if( minAn == an(B,Y+dy[i],X+dx[i]) ) {
					Y+=dy[i];
					X+=dx[i];
					B[Y][X] = 'K';
					break;
				}
		return true;
	}

	int an(vector<string>& B, int Y, int X)
	{
		int dy[]={-2,-2,-1,-1,+1,+1,+2,+2};
		int dx[]={-1,+1,-2,+2,-2,+2,-1,+1};
		int cnt = 0;
		for(int i=0; i<8; ++i)
			cnt += (B[Y+dy[i]][X+dx[i]] == '.');
		return cnt;
	}
};

// BEGIN CUT HERE
#include <ctime>
double start_time; string timer()
 { ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
 { os << "{ ";
   for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
   os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
void verify_case(const int& Expected, const int& Received) {
 bool ok = (Expected == Received);
 if(ok) cerr << "PASSED" << timer() << endl;  else { cerr << "FAILED" << timer() << endl;
 cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
#define END	 verify_case(_, KnightsTour().visitedPositions(board));}
int main(){

CASE(0)
	string board_[] = {
 "........"
,".*.*...."
,".*......"
,"..K...*."
,"*...*..."
,"...*...."
,"...*.*.."
,"........"};
	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int _ = 39; 
END
CASE(1)
	string board_[] = {
 "K......."
,"........"
,"........"
,"........"
,"........"
,"........"
,"........"
,"........"};
	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int _ = 64; 
END
CASE(2)
	string board_[] = {
 "********"
,"*******."
,"********"
,"**.***.*"
,"********"
,"***.*.**"
,"********"
,"****K***"};
	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int _ = 3; 
END
CASE(3)
	string board_[] = {
 "*.*....*"
,".......*"
,"**...*.."
,"..***..."
,".**.*..."
,"..*.*..K"
,"..***.*."
,"**...*.."};
	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int _ = 17; 
END
CASE(4)
	string board_[] = {
 "..*...*."
,"**.....*"
,"*..*...."
,"*..*...."
,".....*.."
,"....*..K"
,"**.*...*"
,"..**...."};
	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int _ = 27; 
END
CASE(5)
	string board_[] = {
 "**.**"
,"K****"
,"**.**"
,"**.*."
};
	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int _ = 3; 
END

}
// END CUT HERE