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 9.2.1) (judge verdict: Accepted)

//114_c
#include <stdio.h>

typedef long long ll;

ll s,N,ans=0;

ll list(ll n,ll a,ll b,ll c){
    if(n>N)return ans;
    if(a>0&&b>0&&c>0)ans++;
    list(n*10+3,a+1,b,c);
    list(n*10+5,a,b+1,c);
    list(n*10+7,a,b,c+1);
}

int main(void){
    scanf("%lld",&N);
    if(N<357){
        printf("0\n");
        return 0;
    }
    printf("%lld\n",list(0,0,0,0));
    return 0;
}