time limit per test: 0.25 sec. memory limit per test: 4096 KB
For given integer N (1<=N<=104) find amount of positive numbers not greater than N that coprime with N. Let us call two positive integers (say, A and B, for example) coprime if (and only if) their greatest common divisor is 1. (i.e. A and B are coprime iff gcd(A,B) = 1).
Input file contains integer N.
Write answer in output file.
Codeforces (c) Copyright 2010-2020 Mike Mirzayanov