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<stdlib.h>
#include<math.h>
#include<string.h>
typedef long long ll;
typedef long double ld;
#define rep(i,l,r)for(ll i=(l);i<(r);i++)
#define repp(i,l,r,k)for(ll i=(l);i<(r);i+=(k))
#define INF (1LL<<60)
#define MOD1 1000000007
#define MAX_N (1 << 17)


void swap(ll *a, ll *b){ll c;c=*b;*b=*a;*a=c;}
ll max2(ll a,ll b){return a>=b?a:b;}
ll min2(ll a,ll b){return a>=b?b:a;}
ll minn(ll n, ll a[n]){ll b=INF;rep(i,0,n) b=min2(b,a[i]);return b;}
ll maxn(ll n, ll a[n]){ll b=-INF;rep(i,0,n) b=max2(b,a[i]);return b;}
ll ABS(ll a){return a>=0?a:(-a);}
ll POW(ll a, ll b){ll c=1;rep(i,0,b) c*=a;return c;}
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}
int upll(const void*a, const void*b){return*(ll*)a<*(ll*)b?-1:*(ll*)a>*(ll*)b?1:0;}
int downll(const void*a, const void*b){return*(ll*)a<*(ll*)b?1:*(ll*)a>*(ll*)b?-1:0;}
void sortup(ll*a,int n){qsort(a,n,sizeof(ll),upll);}
void sortdown(ll*a,int n){qsort(a,n,sizeof(ll),downll);}

/*nをa進数にしたときの、i桁目の数*/
ll placenai(ll n, ll a, ll i){return i==1?n%a:placenai(n/a,a,i-1);}

ll x[3]={0,0,0};

ll dfs(ll a, ll n, ll dig){
    // if(a==0) return dfs(a*10+3,n,dig)+dfs(a*10+5,n,dig)+dfs(a*10+7,n,dig);
    // printf("%lld ",a);
    if(a>n) return 0;
    rep(i,0,dig){
        if(placenai(a,10,i+1)==3) x[0]=1;
        if(placenai(a,10,i+1)==5) x[1]=1;
        if(placenai(a,10,i+1)==7) x[2]=1;
    }
    ll c=x[0]+x[1]+x[2];
    // printf("%lld\n",c);
    rep(i,0,3) x[i]=0;
    return ( c==3?1:0 ) + dfs(a*10+3,n,dig+1)+dfs(a*10+5,n,dig+1)+dfs(a*10+7,n,dig+1);
}


int main(void){
    // char ;
    ll n;
    scanf("%lld",&n);
    printf("%lld\n",dfs(0,n,0));
    return 0;
}