Time Limit: 1 s
Memory Limit: 32 MB

Submission：151
AC：68
Score：96.51

We know that if a phone number A is another phone number B’s prefix, B is not able to be called. For an example, A is 123 while B is 12345, after pressing 123, we call A, and not able to call B.

Given N phone numbers, your task is to find whether there exits two numbers A and B that A is B’s prefix.

The input consists of several test cases.

The first line of input in each test case contains one integer N (0<N<1001), represent the number of phone numbers.

The next line contains N integers, describing the phone numbers.

The last case is followed by a line containing one zero.

For each test case, if there exits a phone number that cannot be called, print “NO”, otherwise print “YES” instead.

input

2
012
012345
2
12
012345
0

output

NO
YES