/*
DATE:3/11/2008
AUTHOR: M DEEPAK
MAIL BUGS TO:mdeepak@cse.iitk.ac.in
*/
/*
2.  Stirling numbers: A stirling number of the first kind is defined as follows
 s(n,0) = 0, for all n > 0
 s(n+1,k) = s(n,k-1) - n*s(n,k), for all n >= 0 and k>0.
 s(0,0) = 1
Write a recursive method to compute stirling number of first kind. Use it in a program
which reads integers n and k from command line and print the corresponding stirling
number.
*/
class Stirling{
	
		public static void main(String args[]){
			
			int n=0;
			int k=0;
			
			try{				
				n=Integer.parseInt(args[0]);
				k=Integer.parseInt(args[1]);
			}catch(Exception e){
				
				System.out.println("Please Enter two numbers as argument");
				System.exit(0);
			}
			
			System.out.println("The numbers entered are n="+n+",k="+k);
			
			System.out.println("Stirling number for  First kind="+stirling(n,k));
			
		}
		public static int stirling(int n,int k){
			
			if((n==0)&&(k==0))
				return 1;
				
		    else if((n>=1)&&(k>0))
		    	return stirling(n-1,k-1)-(n-1)*stirling(n-1,k);
		    	
		    else if(n>0)
		    	return 0;
	
			return 0;	    	
		}
}