/** Mock Lab Test for 18th September 2008***/



/*Write a JAVA program to find the difference between the nth prime number and (n + k)th
prime number for a given pair of a positive integers n and k. For example, if the input value
of n = 2 and k = 3, then the output should be 8 because the 2nd prime number is 3 and 5th
prime number is 11.
Note: The input n and k must be taken from command line in this order.*/

/*keyidea: start from 2 and keep on finding prime numbers till we reach up to n+k th prime number.
 *in between store the nth prime number and print the difference in the end*/
 
class DiffPrime
{
	public static boolean isprime(int num)
	{
		int i = 1;
		int sqroot = (int)Math.sqrt(num);

		if(num==2)
		{
			return true;
		}
		if(num % 2 == 0)
		{
			return false;
		}
		else
		{
			for( i = 3; i <= sqroot; i+=2)
			{
				if (num % i == 0)
				{
					return false;
				}
			}
			return true;
		}
		
			
	}
	
	public static void main(String args[])
	{
		int n = Integer.parseInt(args[0]);
		int k = Integer.parseInt(args[1]);
		
		int count=0;
		int firstprime=0, nextprime=0;
		
		int i= 2;
		while(true)
		{
			if(isprime(i))
			{
				count += 1;
				if(count == n)
				{
					firstprime = i;
				}
				if(count == (n + k))
				{
					nextprime = i;
					System.out.println("the firstprime is" + firstprime + "the second prime is" + nextprime);
					System.out.println("difference is " + (nextprime - firstprime));
					break;
				}
			}
			
			i += 1;
			
		}
	}
}