/*
	THE STARTER FILE FOR 401 XC1  MISSING NUMBER PROBLEM
*/

import java.util.*;
import java.io.*;

public class MissingNumber
{
	public static void main(String[] args) throws Exception
	{
		if ( args.length < 1 )
		{
			System.out.println("MISSING INPUT FILE ON CMD LINE\n");
			System.exit(0);
		}
		BufferedReader infile = new BufferedReader( new FileReader( args[0] ) );

		while ( infile.ready() ) // assume line ->  "6 9 1 5 2 4 3 10 8"  (i.e. its missing 7)
		{
			String[]tokens = infile.readLine().split("\\s+"); // tokens -> ["6"]["9"]["1"]["5"]["2"]["4"]["3"]["10"]["8"]
			int[] arr = new int[ tokens.length ];
			for( int i=0 ; i<tokens.length ; ++i )
			{	arr[i]  = Integer.parseInt( tokens[i] ); // convert. "7" to 7
				System.out.print( arr[i] + " "  );
			}
			//  WE JUST READ ALL THE NUMBERS FROM THE FILE INTO A LITTLE ARRAY

			int missingNumber = findMissingNumber( arr );
			System.out.println( "missing " + missingNumber  );

		} // END WHILE THER IS A ANOTHER LINE IN THE FILE
	} // END MAIN


	/////////////  T H I S   I S  T H E  M E T H O D  Y O U  F I L L  I N  /////////////


	// FIGURE OUT  MISSING NUMBER MAKING ONE PASS OVER THE ARRAY
	// NEVER ALLOWED TO LOOK AT ANY ELEM IN ARRAY MORE THAN ONCE
	static int findMissingNumber( int[] a )
	{
		// YOU MAY DEFINE A FEW INT VARIABLES. NO ARRAYS NO ARRAYLISTS ETC.
		// WRITE 1 LOOP THAT VISITS EACH ELEM IN ARRAY EXACTLY ONCE
		// AFTER THE LOOP IS OVER YOUR VARIABLES SHOULD HAVE VALUES NEEDED
		// TO CALC THE MISSING NUMBER WITH **NO MORE LOOPS** JUST A FEW ARITHMETIC OPERATIONS
		//
		return 0; // RETURN THE MISSING NUMBER HERE
	}

} // END CLASS MissingNumber