Preparando MOJI

Unsolvable

2000ms 262144K

Description:

Consider the following equation:

where sign [a] represents the integer part of number a.

Let's find all integer z (z > 0), for which this equation is unsolvable in positive integers. The phrase "unsolvable in positive integers" means that there are no such positive integers x and y (x, y > 0), for which the given above equation holds.

Let's write out all such z in the increasing order: z1, z2, z3, and so on (zi < zi + 1). Your task is: given the number n, find the number zn.

Input:

The first line contains a single integer n (1 ≤ n ≤ 40).

Output:

Print a single integer — the number zn modulo 1000000007 (109 + 7). It is guaranteed that the answer exists.

Sample Input:

1

Sample Output:

1

Sample Input:

2

Sample Output:

3

Sample Input:

3

Sample Output:

15

Informação

Codeforces

Provedor Codeforces

Código CF225E

Tags

mathnumber theory

Submetido 0

BOUA! 0

Taxa de BOUA's 0%

Datas 09/05/2023 08:39:15

Relacionados

Nada ainda