prime-probablity-1
Source: hackerearth
Difficulty: UNKNOWN_DIFFICULTY

Surya and his girl fiend went on a date during this weekend.There is a sequence of numbers from 1 to 1000000 on a table. Surya picked up a sub sequence SS from it and wants his girl friend to pick a number from SS. What is the probability that the number she picked was a prime number.

Input Format

First Line of input contains T , number of test cases and next T lines contains L and R , the starting number and ending number of the sequence

Output Format

Print the answer with up to 6 digits after the decimal point.

Constraints

1 ≤ T ≤ 100000

1 ≤ L ≤ R ≤ 1000000
Register for IndiaHacksSAMPLE INPUT
2
1 10
3 3

SAMPLE OUTPUT
0.400000
1.000000

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