#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define MAXQUEENS 12

void printboard(int board[], int n)
{
   int i = 0;
   for (i = 0; i < n; i++)
   {	printf("(%d,%d)", i, board[i]);   }
   printf("\n");
}

int checkboard(int board[], int row)
{
   int i = 0;
   for (i = 0; i < row; i++)
   {
      if (board[i] == board[row])
	return 0; /* Same column. */
      if( abs(board[i] - board[row]) == abs(i - row))
	return 0; /* Same diagonal */ 
   }
   return 1;
}

void solve(int board[], int row, int n)
{
   int i = 0;
   /* Base case */
   if (row == n) printboard(board, n);
   else
   {
   /* Recursive case. */
   for (i = 0; i < n; i++)
	{
		board[row] = i;
		if (checkboard(board, row))
		{
			solve(board, row + 1, n);
		}
	}
   }
}


int main()
{
   int board[MAXQUEENS];

   char c = 0;
   int n = 0;

   int pipefd[2];
   pid_t childpid;

   while ((EOF != (c = getchar())) && (c != '\n'))
   {  n = 10 * n + (c - '0');  }

   if (( n <= 0 ) || (n > MAXQUEENS))
   { fprintf(stderr, "Lousy input\n");  }


   // Here is where we begin to depart from the traditional solution.

   if (pipe(pipefd) < 0)     /* Create a pipe. */
     {
       fprintf(stderr, "Pipe error!\n");
       exit(-1);
     }
   
   childpid = fork();        /* fork another process */
   
   if (childpid < 0)         /* Forking error! */
     {   exit(-1);   }
   else if (0 == childpid)   /* Child process */
     {
       close(pipefd[1]);     /* Child closes write end of pipe. */
       dup2(pipefd[0], STDIN_FILENO);
                             /* Hook read end of pipe to stdin. */
       close(pipefd[0]);     /* Clean up duplicate descriptor.  */
       
       /* Replace the child process image with the "more" command. */
       execlp("more", "more", NULL);
       /* Should never get past this line if execlp succeeded. */
     }
   else                      /* Parent process */
     {
       close(pipefd[0]);     /* Parent closes read end of pipe. */
       dup2(pipefd[1], STDOUT_FILENO);
                             /* Hook write end of pipe to stdout. */
       close(pipefd[1]);     /* Clean up duplicate descriptor.  */
       
       solve(board, 0, n);   /* Go solve the N-Queens problem.  */
     }
}