2759. The Lucky Numbers

单点时限: 5.0 sec

内存限制: 256 MB

John and Brus are freshmen at the primary school. Their first home task is to learn some integer numbers. It is not so hard for the guys and they decide to impress their teacher by learning all lucky numbers between $A$ and $B$, inclusive.

As you already know from the previous year contest $4$ and $7$ are lucky digits, and all the other digits are not lucky. A lucky number is a number that contains only lucky digits in decimal notation.

After learning all lucky numbers in $[A, B]$ range John and Brus still have some free time and now they decide to learn additionally each lucky number $N$ that is out of $[A, B]$ range, but the reversed number of $N$ is in this range. Here reversed number of $N$ is the number $N$ written in decimal notation, but the order of digits is reversed. For example, the reversed number of $447$ is $744$ and reversed number of $774474444$ is $444474477$.

You are given integers $A$ and $B$ and your task is to find the total number of lucky numbers learned by John and Brus.


The first line contains single integer $T$ – the number of test cases. Each test case consists of a single line containing two integers $A$ and $B$ separated by a single space.


For each test case print a single line containing the total number of lucky numbers learned by John and Brus.


  • $1 \le T \le 74$,
  • $1 \le A \le B \le 10^{47}$.


1 100
44 47

1 人解决,13 人已尝试。

1 份提交通过,共有 22 份提交。

9.9 EMB 奖励。

创建: 13 年,1 月前.

修改: 4 年,10 月前.

最后提交: 7 月,2 周前.

来源: Southeastern European Regional Programming Contest 2009