题解 | 挑7

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNext()) {
            int maxInt = scanner.nextInt();
            int count = 0;
           for(int i = 7; i <= maxInt; i ++)
           {
               if(i % 7 == 0)
               {
                   count ++;
               }else if(String.valueOf(i).contains("7"))
               {
                   count ++;
               }
           }
           System.out.println(count);
        }
    }
}