Олимпиадный тренинг

Задача . G. Garage


Pak 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.

Input

The only line contains a single integer \(N\) (\(1 \leq N \leq 10^9\)).

Output

An integer that represents the \(N\)-th smallest suitable number.

Note

The \(3\)-rd smallest suitable number is \(7\). A square area of \(7\) can be obtained by assigning \(a=3\) and \(b=4\).


Примеры
Входные данныеВыходные данные
1 3
7

time 1000 ms
memory 128 Mb
Правила оформления программ и список ошибок при автоматической проверке задач

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