Given a positive integer , determine how many of the integers between 1 and are co-prime with .
Two numbers are co-prime if the only common positive factor of the two numbers is 1.
The input will contain one integer ().
Print a single integer--the number of integers between 1 and that are co-prime with .
Input | Output |
---|---|
15 | 8 |
Input | Output |
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20 | 8 |