import sys

def pol(s):

    l = len(s)

    for i in range( l / 2 ):
        if s[i] != s[l - i - 1]:
            return "no"

    return "yes"

try:
    print pol(sys.argv[1])
except:
    open("output.txt", "w").write( pol(open("input.txt").read()) )