今天天气太好了，阳光明媚，大象决定去拜访他的朋友。 大象的家和朋友的家在一条直线上，相距x米。大象一步可以走1米、2米、3米、4米或者5米，请问大象至少需要走多少步才能达到他的朋友的家？
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.
一个整数x(1≤x≤1 000 000)，表示大象的家到朋友家的距离。
The first line of the input contains an integer x (1 ≤ x ≤ 1 000 000) — The coordinate of the friend's house.
大象到朋友家所需要的最小步数。
Print the minimum number of steps that elephant needs to make to get from point 0 to point x.
12
3
样例2输入：
5
样例2输出：
1
In the first sample the elephant needs to make one step of length 5 to reach the point x.
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.