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>
int a[3]={3,5,7};
long cou=0;
long pow10(int r){
    int h=1;
    for(int i=0;i<r;i++)h*=10;
    return h;
}
int hantei(long N){
    int k=0,m,d7=0,d5=0,d3=0,h;
    while(N>0){
        m=N%10;
        if(m!=7 && m!=5 && m!=3)return 0;
        if(m==7)d7++;if(m==5)d5++;if(m==3)d3++;
        N/=10;
        if(N<=0)break;
        k++;
    }
    if(d7>0 && d5>0 && d3>0){h=1;}else{h=0;}
    return h;
}
void seisei(long N,long d,int l){
    long ret=d;
    if(d<=N){
        for(int i=0;i<3;i++){
            d=ret;
            d+=(long)a[i]*pow10(l);
            if(d<=N){cou+=hantei(d);}else{return;}
            seisei(N,d,l+1);
        }
    }
}
int main(void){
    long N;
    scanf("%ld",&N);
    seisei(N,0,0);
    printf("%ld\n",cou);
    return 0;
}