Jason is trying to find which group of the periodic table an element belongs to.

The group of an element is determined by the amount of protons it has.

For example, Hydrogen is in group 1 while oxygen is in group 16

Given an element with atomic number (the amount of protons it has) \(N\) , determine its group.

Constraints

Subtask 1 [40%]

\(19 \le N \le 54\)

Subtask 2 [30%]

\(3 \le N \le 54\)

Subtask 3 [30%]

\(1 \le N \le 54\)

Input Specification

The input contains one integer, \(N\)

Output Specification

Output the one integer, the group that an element with atomic number \(N\) belongs to

Sample Input

19

Sample Output

1

Explanation for Sample Output

The element with atomic number 19 is Potassium and belongs to group 1

Sample Input

2

Sample Output

18

Explanation for Sample Output

The element with atomic number 2 is Helium and belongs to group 18