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 sc = new Scanner(System.in); String str = sc.nextLine(); int k = sc.nextInt(); // String substr = str.substring(0,k); char[] chars = str.toCharArray(); for(int i = 0; ...