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Problems

Rectangle

Rectangle

Time limit 1 second
Memory limit 128 MiB

Four positive integers a, b, c, d are given. Find the sum of the given numbers if there exists a rectangle 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 rectangle exists, print the sum of all numbers. Otherwise print "No".

Examples

Input example #1
7 4 4 7
Output example #1
22
Input example #2
9 9 9 6
Output example #2
No
Author Matviychuk Sergiy Volodymyrovych
Source ABC Programming