n=int(input())
s1=list(map(int,input().split()))
alen=len([item for item in s1 if item<60])
blen=len([item for item in s1 if item>=90])

if alen>0:
    print("no")
else:
    if blen>=5:
        print("1")
    elif blen>=3:
        print("2")
    elif blen==2:
        print("3")
    else:
        pass


/**************************************************************
	Problem: 1429
	User: admin
	Language: Python
	Result: Accepted
	Time:142 ms
	Memory:34480 kb
****************************************************************/