문제

Author: Adrian Satja Kurdija

Mirko works in a sugar factory as a delivery boy. He has just received an order: he has to deliver exactly N kilograms of sugar to a candy store on the Adriatic coast. Mirko can use two types of packages, the ones that contain 3 kilograms, and the ones with 5 kilograms of sugar. Mirko would like to take as few packages as possible. For example, if he has to deliver 18 kilograms of sugar, he could use six 3-kilogram packages. But, it would be better to use three 5-kilogram packages, and one 3-kilogram package, resulting in the total of four packages. Help Mirko by finding the minimum number of packages required to transport exactly N kilograms of sugar.

입력

The first and only line of input contains one integer N (3 ≤ N ≤ 5000).

출력

The first and only line of output should contain the minimum number of packages Mirko has to use. If it is impossible to deliver exactly N kilograms, output -1.

예제 입력 1

4

예제 출력 1

-1

예제 입력 2

9

예제 출력 2

3

예제 입력 3

18

예제 출력 3

4