#include <stdio.h>
#include <stdlib.h>
#define RIGHT 0
#define BOTTOM 1
#define LEFT 2
#define TOP 3
int main()
{
  int matrix[5][5] = {{11,12,13,14,15},{16,17,18,19,20},{21,22,23,24,25},{26,27,28,29,30},{31,32,33,34,35}},check[5][5],i=0,j=0,direction = RIGHT,block[4] = {0,0,1,1};
  for(i=0;i<5;i++)
  {
    for(j=0;j<5;j++)
      check[i][j] = 0;
  }
  i=0;j=0;
  printf("\n");
  while(1)
  {
    printf("%d\t",matrix[i][j]);
    check[i][j] = 1;
    if(direction == RIGHT )
    {
      if( j<4 && check[i][j+1] == 0)
      {
	j=j+1;
      }
      else
      {
	direction = BOTTOM;
	if(i<4 && check[i+1][j] == 0)
	{
	  i = i+1;
	}
	else
	{
	  break;
	}
      }
    }
    else if(direction == BOTTOM )
    {
      if( i<4 && check[i+1][j] == 0)
      {
	i=i+1;
      }
      else
      {
	direction = LEFT;
	if(j>0 && check[i][j-1] == 0)
	{
	  j = j-1;
	}
	else
	{
	  break;
	}
      }
    }
    else if(direction == LEFT )
    {
      if( j>0 && check[i][j-1] == 0)
      {
	j=j-1;
      }
      else
      {
	direction = TOP;
	if(i>0 && check[i-1][j] == 0)
	{
	  i = i-1;
	}
	else
	{
	  break;
	}
      }
    }
    else if(direction == TOP )
    {
      if( i>0 && check[i-1][j] == 0)
      {
	i=i-1;
      }
      else
      {
	direction = RIGHT;
	if(j<4 && check[i][j+1] == 0)
	{
	  j = j+1;
	}
	else
	{
	  break;
	}
      }
    }
  }
  printf("\n");    
  return 0;
}