SCC0106 - Editorial

### PROBLEM LINK:

### PROBLEM NAME: Who is my friend.

**Author:** Learners Club

### DIFFICULTY:

EASY-MEDIUM

### PREREQUISITES:

Prime Numbers, Euler Totient function

### PROBLEM:

In short, We are required to find the count of all the positive numbers less than N which are coprime to the given number N.

### EXPLANATION:

This is a direct application of Euler Totient Function.

Look up wikipedia to understand it and give it a try on the practice section.

Important point to know is that For N = 1 the Answer is 1, Find out why… ?