7666: [CSES Problem Set] Bracket Sequences I
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Description
Your task is to calculate the number of valid bracket sequences of length $n$.
For example, when $n=6$, there are $5$ sequences:
For example, when $n=6$, there are $5$ sequences:
-
()()()
-
()(())
-
(())()
-
((()))
- (()())
Input
The only input line has an integer $n$.
Output
Print the number of sequences modulo $10^9+7$.
Constraints
$1≤n≤10^6$
Sample 1 Input
6
Sample 1 Output
5