We will divide all students into several groups, and in each group they will discuss some topics. You think that groups of two or less students cannot discuss effectively, so you want to have as many groups as possible, consisting of three or more students. Separate the students so that the number of groups of three or more students is maximum.
Input
The input is an integer
N (
\(1<=N<=1000\)) - the number of all students.
Imprint
Print one number - the maximum number of groups that can be formed.
Examples
| # |
Input |
Output |
| 1 |
8 |
2 |
| 2 |
2 |
0 |
| 3 |
9 |
3 |