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## I. Interesting Numbers

Time limit: 2.0 second
Memory limit: 64 MB
Nikolay and Asya investigate integers together in their spare time. Nikolay thinks an integer is interesting if it is a prime number. However, Asya thinks an integer is interesting if the amount of its positive divisors is a prime number (e.g., number 1 has one divisor and number 10 has four divisors).
Nikolay and Asya are happy when their tastes about some integer are common. On the other hand, they are really upset when their tastes differ. They call an integer satisfying if they both consider or do not consider this integer to be interesting. Nikolay and Asya are going to investigate numbers from segment [L; R] this weekend. So they ask you to calculate the number of satisfying integers from this segment.

### Input

In the only line there are two integers L and R (2 ≤ LR ≤ 1012).

### Output

In the only line output one integer — the number of satisfying integers from segment [L; R].

### Samples

inputoutput
3 7
4
2 2
1
77 1010
924
Problem Author: Alexey Danilyuk
Problem Source: Ural Regional School Programming Contest 2015
To submit the solution for this problem go to the Problem set: 2070. Interesting Numbers