import sys
import re

def write_answer(answer):
    with open(output_file, 'a') as file:
        file.write(answer+'\n')


input_file = 'test.in'
output_file = 'test.out'
# input_file = sys.argv[1]
# output_file = sys.argv[2]
pattern = re.compile(r'^[1-9a-fA-F][0-9a-fA-F]*$')
with open(output_file, 'w') as readed_output_file:
    with open(input_file, 'r') as readed_input_file:
        for row_input_file in readed_input_file:
            if pattern.search(row_input_file):
                write_answer('yes')
            else:
                write_answer('no')