You are given a string S consisting of lowercase English letters. Determine whether all the characters in S are different.
s = str(input())
dp=0
for i in range(len(s)):
    for j in range(len(s)):
        if s[i] == s[j]:
            dp += 1

if dp == 0:
    print("yes")
else:
    print("no")
s = str(input())
dp=0
for i in range(len(s)-1):
    for j in range(i+1,len(s)):
        if s[i] == s[j]:
            dp += 1

if dp == 0:
    print("yes")
else:
    print("no")