e-olymp
Competitions

Programming Principles 1. Week 2. September 9 - 15. PART 3

Square

Four positive integers a, b, c, d are given. Find the square of any given number if there exists a square with side lengths a, b, c, d and No otherwise.

Input

Four positive integers a, b, c, d, each no more than 109.

Output

If the square exists, print the square of any input number. Otherwise print No.

Time limit 1 second
Memory limit 128 MiB
Input example #1
7 7 7 7
Output example #1
49
Input example #2
9 6 9 6
Output example #2
No
Author Matviychuk Sergiy Volodymyrovych
Source "ABC programming"