Petya loves lucky numbers. We all know that lucky numbers are the positive integers whose decimal representations contain only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.

One day Petya came across an interval of numbers $[*a*, *a* + *l* - 1]$. Let $*F*(*x*)$ be the number of lucky digits of number $*x*$. Find the minimum $*b*$ $(*a* < *b*)$ such, that $*F*(*a*)$ = $*F*(*b*)$, $*F*(*a* + 1)$ = $*F*(*b* + 1)$, ..., $*F*(*a* + *l* - 1)$ = $*F*(*b* + *l* - 1)$.

Input

The single line contains two integers $*a*$ and $*l*$ ($1 ≤ *a*, *l* ≤ 10^{9}$) — the interval's first number and the interval's length correspondingly.

Output

On the single line print number $*b*$ — the answer to the problem.

Note

Consider that $[*a*, *b*]$ denotes an interval of integers; this interval includes the boundaries. That is,