Multiplying Digits

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Picture by Mees de Vries

For every positive integer we may obtain a non-negative integer by multiplying its digits. This defines a function $f$, e.g. $f(38) = 24$.

This function gets more interesting if we allow for other bases. In base $3$, the number $80$ is written as $2222$, so: $f_3(80) = 16$.

We want you to solve the reverse problem: given a base $B$ and a number $N$, what is the smallest positive integer $X$ such that $f_ B(X) = N$?

Input

The input consists of a single line containing two integers $B$ and $N$, satisfying $2 < B \leq 10\, 000$ and $0 < N < 2^{63}$.

Output

Output the smallest positive integer solution $X$ of the equation $f_ B(X) = N$. If no such $X$ exists, output the word “impossible”. The input is carefully chosen such that $X < 2^{63}$ holds (if $X$ exists).

Sample Input 1 Sample Output 1
10 24
38
Sample Input 2 Sample Output 2
10 11
impossible
Sample Input 3 Sample Output 3
9 216
546
Sample Input 4 Sample Output 4
10000 5810859769934419200
5989840988999909996