(백준) 2902번 : KMP는 왜 KMP일까? - 자바[JAVA]

package test;

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Test_2902 {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();

		String str = br.readLine();
		char ch;

		sb.append(str.charAt(0));

		for(int i = 1; i < str.length(); i++) {
			ch = str.charAt(i);
			if('A' <= ch && ch <= 'Z') {
				sb.append(ch);
			}
		}
		sb.append("\n");
		System.out.println(sb);
	}
}