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: Runtime Error)

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

int func(int n, int N);

//Nが七五三数ならば1，そうでなければ0を返す関数
int judge(int N);

int main(void){
  int N;
  scanf("%d", &N);

  printf("%d\n", func(0, N));
  return 0;
}

int func(int n, int N){
  int ret;//retはreturnの略

  if(n > N){
    return 0;
  }

  if(judge(n) == 1){
    ret = 1;
  }else{
    ret = 0;
  }

  ret += func(n*10 + 3, N) + func(n*10 + 5, N) + func(n*10 + 7, N);

  return ret;
}

int judge(int N){
  int l;//Nの桁数
  int i, j, k;//カウンタ
  int s[20] = {};
  int state = 1;//Nが準七五三数ならば1，そうでなければ0
  int state_3 = 0;//Nに3が含まれれば1，そうでなければ0
  int state_5 = 0;//Nに5が含まれれば1，そうでなければ0
  int state_7 = 0;//Nに7が含まれれば1，そうでなければ0

  //Nの桁数lを求める
  for(i = 0; i < 20; i++){
    if(N >= pow(10, i) && N < pow(10, i+1)){
      l = i+1;
      break;
    }
  }

  //Nを文字列に変換
  for(i = 0; i < l; i++){
    s[i] = N%10 + '0';
    N /= 10;
  }

  //Nが準七五三数かどうかを確かめる
  for(i = 0; i < l; i++){
    if(s[i] != '3' && s[i] != '5' && s[i] != '7'){
      state = 0;
    }
  }
  //Nが準七五三数であるとき，Nが七五三数かどうかを確かめる
  if(state == 1){
    for(i = 0; i < l; i++){
      if(s[i] == '3'){
        state_3 = 1;
      }
    }
    for(i = 0; i < l; i++){
      if(s[i] == '5'){
        state_5 = 1;
      }
    }
    for(i = 0; i < l; i++){
      if(s[i] == '7'){
        state_7 = 1;
      }
    }
  }

  if(state == 1 && state_3 == 1 && state_5 == 1 && state_7 == 1){
    return 1;
  }
  else{
    return 0;
  }
}