617A. Elephant

617A. Elephant

617A. Elephant

• time limit per test1 second
• memory limit per test256 megabytes
• inputstandard input
• outputstandard output

An elephant decided to visit his friend. It turned out that the elephant's house is located at point 0 and his friend's house is located at point x(x > 0) of the coordinate line. In one step the elephant can move 1, 2, 3, 4 or 5 positions forward. Determine, what is the minimum number of steps he need to make in order to get to his friend's house.

一头大象决定去拜访他的朋友。事实证明，大象的房子位于0点，而他的朋友的房子位于x点（x） > 坐标线的0）。在一个步骤中，大象可以向前移动1、2、3、4或5个位置。确定他到达朋友家所需的最小步数。

Input

The first line of the input contains an integer x (1 ≤ x ≤ 1 000 000) — The coordinate of the friend's house.

输入的第一行包含一个整数x（1） ≤ 十、 ≤ 1. 000 000）-朋友家的坐标。

Output

Print the minimum number of steps that elephant needs to make to get from point 0 to point x.

打印大象从0点到x点所需的最小步数。

Examples

input1

5

output1

1

input2

12

output2

3

Note

In the first sample the elephant needs to make one step of length 5 to reach the point x.

在第一个样本中，大象需要走5步才能到达x点。

In the second sample the elephant can get to point x if he moves by 3, 5 and 4. There are other ways to get the optimal answer but the elephant cannot reach x in less than three moves.

在第二个样本中，如果大象移动3、5和4，就可以到达x点。还有其他方法可以获得最佳答案，但大象不可能在三步之内到达x。