import string
key = list(string.ascii_lowercase)

S = input()
s = [[S[i*2+j] for i in range(len(S) // 2)] for j in range(2)]

s1 = list(set(s[0]) - set(key))
s2 = list(set(s[1]) - set([' ']))

print(['No', 'Yes'][len(s1) + len(s2) == 0])