# s,e,N = input().split(" ")
# if int(N)<=1:
#     print(-1)
# else:
#     print(s+'a'*(int(N)-2)+e)
import re
A,B = input().split(" ")
result = re.sub(r'\d', '',A+B)
assert(0==len(result))
#print(int(A)+int(B))