Like other girlfriends Chintu's girlfriend is also very demanding. This time she is demanding for bracelet having atleast k special beads. A bracelet is composed of N strands. Each strand can have any number of beads and each bead has a letter engraved on it. A bead is called a special bead if the letter engraved on it occurs atleast once in each strand of a bracelet. To fulfill his girlfriend's demand Chintu went to a shop to buy that bracelet for her. But unluckily that shop has got only one piece of that bracelet left. Now you need to find whether Chintu will be able to fulfill his girlfriend's demand or not.

Input:
The first line of input consists of two numbers N and k. N represents the number of strands and k represents the minimum number of special beads.Each of the next N lines contain each strands' composition. Each composition consists of lowercase letters of English alphabet.

Output :
Print ":-)" without quotes if Chintu is able to fulfill his girlfriend's demand, if not then print ":-(".

Constraints:
1 ≤ N ≤ 100 

1 ≤ K ≤ 26

Each composition consists of only small latin letters ('a'-'z'). 

1 ≤ Length of each composition ≤ 100

SAMPLE INPUT
3 2
abcde
aabaa
asdba

SAMPLE OUTPUT
:-)

Explanation

First strand contains 5 special elements(a,b,c,d,e)
Second strand contains 2 special elements(a,b)
Third strand contains 4 special elements(a,s,d,b)
But only two special elements (a,b) are common in all three strands
n,k=map(int,raw_input().split())
ans=set([chr(i) for i in xrange(97,97+26+1)])
for _ in xrange(n):
	ans=ans.intersection(set(list(raw_input())))

if len(ans)>=k:
	print ":-)"
else:
	print ":-("