# Cut Ribbon

## 题目描述

Polycarpus 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 Polycarpus and find the number of ribbon pieces after the required cutting.

## 输入输出格式

### 输入格式

The first line contains four space-separated integers \$ n \$ , \$ a \$ , \$ b \$ and \$ c \$ \$ (1<=n,a,b,c<=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.

### 输出格式

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

## 输入输出样例

### 输入样例 #1

``````5 5 3 2
``````

### 输出样例 #1

``````2
``````

### 输入样例 #2

``````7 5 5 2
``````

### 输出样例 #2

``````2
``````

## 说明

In the first example Polycarpus can cut the ribbon in such way: the first piece has length 2, the second piece has length 3. In the second example Polycarpus can cut the ribbon in such way: the first piece has length 5, the second piece has length 2.