# -*- coding: utf-8 -*-
old = [int(i) for i in input().split(".")]
judging = [int(i) for i in input().split(".")]

result = "YES"

for i in range(len(old)):
    
    if judging[i] < old[i]:
        result = "YES"
        break
    elif old[i] < judging[i]:
        result = "NO"
        break
    else:
        pass
    
print(result)