G. Garagetime limit per test1 secondmemory limit per test128 megabytesinputstandard inputoutputstandard outputPak Chanek plans to build a garage. He wants the garage to consist of a square and a right triangle that are arranged like the following illustration.  Define a and b as the lengths of two of the sides in the right triangle as shown in the illustration. An integer x is suitable if and only if we can construct a garage with assigning positive integer values for the lengths a and b (a<b) so that the area of the square at the bottom is exactly x. As a good friend of Pak Chanek, you are asked to help him find the N-th smallest suitable number.InputThe only line contains a single integer N (1 \leq N \leq 10^9).OutputAn integer that represents the N-th smallest suitable number.ExampleInput
3
Output
7
NoteThe 3-rd smallest suitable number is 7. A square area of 7 can be obtained by assigning a=3 and b=4.
3

7 
['binary search', 'geometry', 'math', '*1500']