inputer =input() inputer_s =inputer.split(" ") inputer_s.sort() count_time = 0 result=0 while count_time <4: if count_time >0: if int(inputer_s[count_time])-tmp==1: result=result+1 tmp_d=int(inputer_s[count_time]) count_time=count_time+1 if result ==3: print("Yes") else: print("No")