#!/usr/bin/python3

import re

def is_number(test):
    pattern = re.compile(r'^N(IE{6}|O{6})!{3}$')
    
    result = re.match(pattern, test)
    if result:
        return "yes"
    else:
        return "no"

x = input()
while x:
    print(is_number(x))
    x = input()