字符串不相等

我正在努力找出我的代码出了什么问题。当用户输入为“ apple”时，我得到它不是以元音开头的。请帮忙。

import java.util.*;
public class StringeExerciseElearn {

public static void main(String[] args) {
    // TODO Auto-generated method stub

    Scanner k = new Scanner(System.in);
    System.out.println("Type a word: ");
    String input = k.next();
    String l = input.substring(0);
    String a = "a";
    String e = "e";
    String i = "i";
    String o = "o";
    String u = "u";




    if(l.equals(a) || l.equals(e) || l.equals(i) || l.equals(o) || l.equals(u))
        System.out.println(input + " begins with a vowel!");
    else
        System.out.println(input + " doesn't begin with a vowel");
    }
}

问题来源：stackoverflow