A perfect number is a positive integer that equals the sum of all its proper divisors (divisors smaller than the number itself).
For example, 6 is perfect because its divisors are 1, 2, and 3, and 1 + 2 + 3 = 6.
Read a positive integer n and print Yes if it is a perfect number, or No otherwise.
One positive integer:
nPrint Yes or No.
Input:
6
Output:
Yes
Input:
28
Output:
Yes
Input:
4
Output:
No