题解 | #挑7#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            int number = sc.nextInt();
            int count = 0;
            for (int i = 6; i <= number; i++) {
                if (i % 7 == 0) {
                    count++;
                } else if (String.valueOf(i).contains("7")) {
                    count++;
                }
            }
            System.out.println(count);
        }
        sc.close();
    }
}