Page not loading? Try clicking here.
Placeholder

#2813

Prime number 3 1s 128MB

Problems

A prime number is a natural number greater than 1 that has exactly two divisors: 1 and itself.

Write a program that, given two natural numbers M and N, counts the number of prime numbers between M and N inclusive.


Input

Two natural numbers M and N are given. (1 ≤ M ≤ N ≤ 10\,000\,000)


Output

Print a single integer: the number of prime numbers between M and N inclusive.


Example 

10 100
21


Source

jungol

You must sign in to write code.