Huseyn has a ribbon, its length is $n$. He wants to cut the ribbon in a way that fulfils the following two conditions: \begin{itemize} \item After the cutting each ribbon piece should have length $a, b$ or $c$. \item After the cutting the number of ribbon pieces should be maximum. \end{itemize} Help Huseyn and find the number of ribbon pieces after the required cutting. \InputFile The first line contains four space-separated integers $n, a, b$ and $c~(1 \le n, a, b, c \le 4000)$ --- the length of the original ribbon and the acceptable lengths of the ribbon pieces after the cutting, correspondingly. The numbers $a, b$ and $c$ can coincide. \OutputFile Print a single number --- the maximum possible number of ribbon pieces. It is guaranteed that at least one correct ribbon cutting exists.