题解 | #挑7#

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n=in.nextInt();
        int num=0;
        for(int i=7;i<=n;i++){
            if(i%7==0||String.valueOf(i).contains("7")){
                num++;
            }
        }
        System.out.println(num);
    }
}