Execution result memo of String.substring

public class Sample {
	public static void main(String[] args) {
		String str = "AIUEO";
		System.out.println(str.substring(0,3)); // ->Ah
		System.out.println(str.substring(3));   // ->Eo
		System.out.println(str.substring(0, str.indexOf("U"))); // ->Ai
	}
}

I can't always remember the movement of the substring, so I write a snippet every time, so I'll write it down.