题解 | #截取字符串#

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 in = new Scanner(System.in);
        String str = in.nextLine();
        int k = in.nextInt();
        int len = str.length();
        if(len==0 || len>1000 || k<0 || k>len){
            return;
        }
        System.out.println(str.substring(0,k));
    }
}