Problems
Split into composite numbers
Split into composite numbers
What is the largest number of composite integers can be used to represent the number n as a sum of composite numbers?
Note: A positive integer that has a divisor other than itself and 1 is called a composite.
Input data
One integer n (1 ≤ n ≤ 10^18
).
Output data
Print the largest number of composite integers that can be used so that their sum equals n. If n cannot be represented as a sum of composite numbers, print -1.
Examples
Input example #1
8
Output example #1
2
Input example #2
6
Output example #2
1
Input example #3
15
Output example #3
2
Input example #4
7
Output example #4
-1