HZNUOJ

Phone Number

Tags:
Time Limit:  1 s      Memory Limit:   32 MB
Submission:143     AC:67     Score:96.51

Description

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.

Input

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.

Output

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

Samples

input
2 012 012345 2 12 012345 0
output
NO YES

Source

山东省第一届大学生程序设计竞赛