Task
           Time limit: 
1000 ms,
           
Memory limit: 
256 Mb
           Non-negative integers n and k are given. It is necessary to output the number of combinations of n by k.
The formula for the number of combinations (you must remember that 0! = 1):
\(C^k_n=\frac{n!}{k!(n-k)!}\)
Input: integers n and k, each from a new line (each number is not more than 10, 
\(n >= k\))
Output: need to print one number in response
Example
	
		
			| № | 
			Input | 
			Output | 
		
	
	
		
			| 1 | 
			3 
			2 | 
			3 | 
		
		
			| 2 | 
			4 
			4 | 
			1 |