题解 | #单组_补充前导零#

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
	//将整形转化为字符串
        String num = Integer.toString(n);
        int len = num.length();
        char a = '0';
        for (int i = 0; i < (9 - len); i++) {
            num = a + num;
        }
        System.out.println(num);
    }
}