# [UVA10533]Digit

Posted by John on 2016-01-13
Words 508 and Reading Time 2 Minutes
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A prime number is a positive number, which is divisible by exactly two diﬀerent integers.

A digit prime is a prime number whose sum of digits is also prime. For example the prime number 41 is a digit prime because 4 + 1 = 5 and 5 is a prime number. 17 is not a digit prime because 1 + 7 = 8, and 8 is not a prime number.

In this problem your job is to ﬁnd out the number of digit primes within a certain range less than 1000000.

## Input

First line of the input ﬁle contains a single integer N (0 < N ≤ 500000) that indicates the total number of inputs. Each of the next N lines contains two integers t1 and t2 (0 < t1 ≤ t2 < 1000000).

## Output

For each line of input except the ﬁrst line produce one line of output containing a single integer that indicates the number of digit primes between t1 and t2 (inclusive).

## Sample Input

3 10 20 10 100 100 10000

## Sample Output

1 10 576

Note: You should at least use scanf() and printf() to take input and produce output for this problem. cin and cout is too slow for this problem to get it within time limit.

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