Problems

# Cut ribbon

# Cut ribbon

Huseyn has a ribbon, its length is n. He wants to cut the ribbon in a way that fulfils the following two conditions:

After the cutting each ribbon piece should have length a, b or c.

After the cutting the number of ribbon pieces should be maximum.

Help Huseyn and find the number of ribbon pieces after the required cutting.

## Input data

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.

## Output data

Print a single number — the maximum possible number of ribbon pieces. It is guaranteed that at least one correct ribbon cutting exists.

## Examples

Input example #1

22 5 2 3

Output example #1

11