题解 | #判断字母#

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        char zf = scanner.next().charAt(0);
        int x = -1;
        for(char i = 'a', j = 'A'; i <= 'z' && j <= 'Z'; i++, j++) {
            if(zf == i || zf == j) {
                System.out.println("YES");
                x = 1;
                break;
            }
        }
        if(x == -1) {
            System.out.println("NO");
        }
    }
}