Competitions
Оператор розгалуження
Square
Four positive integers a, b, c, d are given. Find the square of any number if there exists a square with side lengths a, b, c, d. Print No otherwise.
Input data
Four positive integers a, b, c, d, each no more than 10^9.
Output data
If the square exists, print the square of any number. Otherwise print No.
Examples
Input example #1
7 7 7 7
Output example #1
49
Input example #2
9 6 9 6
Output example #2
No