Pronic Number
A pronic number is a product of two consecutive integers, k(k+1) (0, 2, 6, 12, 20, ...). Is N pronic?
Input: one integer N.
Output: YES or NO.
Constraints:
- 1 ≤ N ≤ 109
Sample Tests
Input 1
12
Output 1
YES
Input 2
13
Output 2
NO
Discussion (opens after you solve — no spoilers before)
No comments yet.