Sum of magic Numbers:
Given a number X,return "YES" if it can be represented as a sum of magic number, or return "NO",if it can not be represented as one.
Here magic number is defined as a number Y=n*(n+1)/2;
Therefore ,to find if X=Y+Z is possible where Y and Z are magic numbers.
TEST CASE 1:
Input:7
Output:YES
EXPLANATION:7=1+6,where 1 and 6 are magic numbers because 1=1(1+1)/2 and 6=3(3+1)/2.