runtime error

안녕하세요 선생님,
채점하면 런타임 에러 나오는데.. 코드 한 번 봐주실 수 있을까요?

import java.util.Scanner;

public class Main {

  public static void main(String[] args){

    Scanner in=new Scanner(System.in);

    int n = in.nextInt();

    String str = in.nextLine();

    in.close();

    String result = password(str,n);

    System.out.println(result);

  }

  public static String password(String s, int n){

    String result = "";

    for(int i=0;i<n;i++){

      String sub = s.substring(0,7).replace('#','1').replace('*','0');

      int num = Integer.parseInt(sub,2);

      result += (char)num;

      s = s.substring(7);

    }

    return result;

  }

}

public class Main {

  public static void main(String[] args){

    Scanner in=new Scanner(System.in);

    int n = in.nextInt();

    in.nextLine();
    String str = in.nextLine();

    in.close();

    String result = password(str,n);

    System.out.println(result);
  }