Problems
My favorite, irreducible...
My favorite, irreducible...
“Название задачи можно напевать на мотив марша или строевой песни…”
How many irreducible fractions exist in the interval [0..1] with denominator not exceeding n?
Input
One positive integer n (n < 10001).
Output
Print the number of irreducible fractions in the interval [0..1] with denominator not exceeding n.
Input example #1
5
Output example #1
9
Input example #4
6
Output example #4
11