Problem Statement
Let $X = 10^{100}$. Inaba has $N$ checker pieces on the number line, where the $i$-th checker piece is at coordinate $X^{i}$ for all $1 \leq i \leq N$.
Every second, Inaba chooses two checker pieces, $A$ and $B$, and move $A$ to the symmetric point of its current position with respect to $B$. After that, $B$ is removed. (It is possible that $A$ and $B$ occupy the same position, and it is also possible for $A$ to occupy the same position as another checker piece after the move).
After $N - 1$ seconds, only one checker piece will remain. Find the number of distinct possible positions of that checker piece, modulo $10^{9} + 7$.
Constraints
$1 \leq N \leq 50$$N$is an integer.
Input
Input is given from Standard Input in the following format:
N
Output
Print the number of distinct possible positions of the final checker piece, modulo $10^{9} + 7$.
样例
3
12
4
84
22
487772376
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