题目描述
Problem Statement
You are given an integer N. Among the integers between 1 and N (inclusive), how many Shichi-Go-San numbers (literally "Seven-Five-Three numbers") are there?
Here, a Shichi-Go-San number is a positive integer that satisfies the following condition:
- When the number is written in base ten, each of the digits 7, 5 and 3 appears at least once, and the other digits never appear.
Input
Input is given from Standard Input in the following format:
N
Output
Print the number of the Shichi-Go-San numbers between 1 and N (inclusive).
Constraints
- $1 \leq N < 10^9$
- N is an integer.
Sample Input 1
575
Sample Output 1
4
There are four Shichi-Go-San numbers not greater than 575: 357, 375, 537 and 573.
Sample Input 2
3600
Sample Output 2
13
There are 13 Shichi-Go-San numbers not greater than 3600: the above four numbers, 735, 753, 3357, 3375, 3537, 3557, 3573, 3575 and 3577.
Sample Input 3
999999999
Sample Output 3
26484
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分