import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
######################################################################

s = input()
t = input()

x1, x2, x3 = 0,0,0

for i in range(len(s)):
    if s[i] == t[i]:
        continue
    elif s[i] > t[i]:
        No()
        exit()
    elif s[i] == "A" and t[i] == "B":
        x1 += 1
    elif s[i] == "A" and t[i] == "C":
        x2 += 1
    elif s[i] == "B" and t[i] == "C":
        x3 += 1

if x1 == x2 == x3 == 0:
    Yes()
elif x1 == x3 and x1 > 0:
    Yes()
else:
    No()