C. Double Happinesstime limit per test3 secondsmemory limit per test128 megabytesinputstandard inputoutputstandard outputOn the math lesson a teacher asked each pupil to come up with his own lucky numbers. As a fan of number theory Peter chose prime numbers. Bob was more original. He said that number t is his lucky number, if it can be represented as: t = a2 + b2,  where a, b are arbitrary positive integers.Now, the boys decided to find out how many days of the interval [l, r] (l ≤ r) are suitable for pair programming. They decided that the day i (l ≤ i ≤ r) is suitable for pair programming if and only if the number i is lucky for Peter and lucky for Bob at the same time. Help the boys to find the number of such days.InputThe first line of the input contains integer numbers l, r (1 ≤ l, r ≤ 3·108).OutputIn the only line print the number of days on the segment [l, r], which are lucky for Peter and Bob at the same time.ExamplesInput3 5Output1Input6 66Output7
Input3 5
Output1
['brute force', 'math', 'number theory', '*2200']