Strategic Arrays

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Points: 15 (partial)
Time limit: 1.0s
Memory limit: 128M

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Problem type

For any 1-indexed array of consecutive positive integers [1,2,,N] a subsequence [a1,a2,,ak] constructed from the first array is considered strategic if every term with an odd index in the subsequence is odd and every term with an even index is even.

A subsequence is a sequence which is derived from the original sequence by deleting zero or more elements without changing the order of the remaining elements.

Given an integer N, print the number of strategic subsequences of [1,2,,N], modulo 109+7.

Constraints

For all subtasks: 1N1018

Subtask 1 [10%]

1N15

Subtask 2 [30%]

1N106

Subtask 3 [60%]

No additional constraints.

Input Specification

You will receive one line of input containing the positive integer N.

Output Specification

Output the number of strategic subsequences, modulo 109+7.

Sample Input

Copy
4

Sample Output

Copy
7

Explanation

The strategic subsequences of [1,2,3,4] are: [1],[3],[1,2],[1,4],[3,4],[1,2,3],[1,2,3,4]


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