BALLSUM  Ball sum
You have a bag filled with N balls.Each Ball has a distinct number from 1 to N printed on it.All the numbers are distinct. You withdraw two balls from the bag and take their sum. You need to calculate the probability that the sum is not greater than the given number K(<=N). The Answer should be displayed in the form of p/q.(except when the answer is 0 or 1)
Input
Input consists of various test cases. Each test case consist of two integer inputs,N and K. (0<=K<=N<=1000000000) The program stops taking input when N and K equals 1
Output
Output the result in the form of p/q.(Except when the answer is 0 or 1)
Example
Input: 3 2 100 5 10 6 1 1 Output: 0 2/2475 2/15
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kass_97:
20161230 12:30:37
Took paper and pen, did some thinking and bingo....AC 

mrx:
20161211 05:57:12
I don't know why I got TLE. I calculated p and q using maths in O(1) and their gcd using recursion and I used C :/


kira28:
20161208 21:04:22
#elementary_school_maths


rrm_2016:
20161126 21:27:40
Lol...that "/" in "p/q" made me submit one wrong solution...otherwise this is a very eazzyy problem..just high school combinatorics Last edit: 20161126 21:27:58 

hacker_sk:
20160926 11:06:20
as written, it's simple math.. AC in one :) 

abhimanyu1996:
20160804 10:53:40
AC in one. #CHAMP 

binari:
20160801 22:09:33
Why my code gives wa, I think my code works correct in every status, by the way what should be written when n=0 and k=0 or n=1,k=1 (inputs like this)? 

cnexans:
20160619 18:38:55
One of the first problems I solve... O(n) solutions won't work. Although there may be many solutions that can be expressed as a loop, you may find one that has a closed formula :) 

vineetpratik:
20160618 17:56:08
o(n) solution won't work


Shubham Pandey:
20160606 20:41:55
Author should have framed question properly , problem statement doesn't apply to n<2 
Added by:  Prateek Agarwal 
Date:  20151215 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 GOSU JSMONKEY 