At the Department of "Applied Informatics" University N in the new academic year recruited three groups of first-year students. For practical exercises, it is necessary to equip a new audience with laboratory tables. No more than four students can sit at each such table, and all students must be from the same group. The audience has the opportunity to simultaneously accommodate students from three groups at once.
Determine the minimum number of tables to be purchased.
Input
The program receives as input three natural numbers (one number per line): the number of students in each of the three groups.
Imprint
Print the answer to the problem.
Examples
| # |
Input |
Output |
| 1 |
15
20
24 |
15 |
Запрещенные операторы:==;if;!=