Problem:
Score : 300 points

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.

Constraints

1 \leq N < 10^9

N is an integer.

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).

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

Solution in C (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
#include<string.h>
#include<stdlib.h>

typedef long long int ll;

ll N;

int count753(ll x){
    int ret = 0;
    if(x > N) return 0;
    char s[10];
    sprintf(s, "%lld", x);
    if(strstr(s, "3") != NULL && strstr(s, "5") != NULL && strstr(s, "7") != NULL) ret = 1;
    return ret + count753(x*10 + 3) + count753(x*10 + 5) + count753(x*10 + 7);
}

int main(){
    scanf("%lld", &N);
    printf("%d\n", count753(0));
    return 0;
}