My favorite, irreducible...
Easy
Execution time limit is 1 second
Runtime memory usage limit is 128 megabytes
“Название задачи можнонапевать на мотив маршаили 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.
Examples
Input #1
Answer #1
Input #4
Answer #4
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