#767. Twin primes
You are given n. Count the pairs where p and p+2 are both prime and p+2 ≤ n.
### Input
One integer n (1 ≤ n ≤ 5000).
### Output
A number.
Examples
Input
4342
Output
115
Input
4555
Output
119
💡 You can solve it with Python, JavaScript or blocks. Read the input line by line with input(). Don't print a question (like input("Number: ")). Print exactly what the output asks for, nothing more.