## DMOPC '21 Contest 10 P5 - Number Theory

View as PDF

Points: 20 (partial)
Time limit: 2.0s
Memory limit: 256M

Author:
Problem types

Find an odd integer with such that .

For any positive integer ,

• is the number of integers between and inclusive that are coprime to .
• is the number of positive divisors of .

#### Input Specification

There is no input for this problem.

Output .

#### Scoring

If your output is improperly formatted, is even, or does not satisfy and , you will receive points.

Otherwise, your score will be . For full points, must be less than .

#### Sample Output

6

#### Explanation

Note that and , so this value of satisfies .

Unfortunately, this value of is not odd, so it would score points.