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: Wrong Answer)

#include <stdio.h>
#include <string.h>
#define rep(i, a) for (int i = 0; i < (a); i++)

int dp[10][2][2][2][2]; // pos, less, has 3, has 5, has 7

int num(int x)
{
    if (x < 3)
        return 0;
    if (x < 5)
        return 1;
    if (x < 7)
        return 2;
    else
        return 3;
}

int main()
{
    char A[10];
    int b[] = {3, 5, 7};
    scanf("%s", A);
    int n = strlen(A);
    dp[0][0][0][0][0] = 1;
    rep(i, n) rep(j, 2) rep(k, 2) rep(l, 2) rep(m, 2)
    {
        int lim = j ? 3 : num(A[i]);
        for (int e = 0; e < lim; e++)
        {
            int d = b[e];
            dp[i + 1][j || d < lim][k || d == 3][l || d == 5][m || d == 7] += dp[i][j][k][l][m];
        }
    }
    int ans = 0;
    rep(j, 2) ans += dp[n][j][1][1][1];
    printf("%d\n", ans);
}