ACM ICPC

题意翻译

有六个整数a1, a2, a3, a4, a5, a6, 它们都小于等于1000。现在希望你把这六个整数分成和相等的两组，如果能，输出"YES"， 如果不能， 输出"NO"。 本题输出大小写不限，即"YeS", 和"yes"也被认作"YES" 感谢@lukelin 提供的翻译

题目描述

In a small but very proud high school it was decided to win ACM ICPC. This goal requires to compose as many teams of three as possible, but since there were only $ 6 $ students who wished to participate, the decision was to build exactly two teams. After practice competition, participant number $ i $ got a score of $ a_{i} $ . Team score is defined as sum of scores of its participants. High school management is interested if it's possible to build two teams with equal scores. Your task is to answer that question.

输入输出格式

输入格式

The single line contains six integers $ a_{1},...,a_{6} $ ( $ 0<=a_{i}<=1000 $ ) — scores of the participants

输出格式

Print "YES" (quotes for clarity), if it is possible to build teams with equal score, and "NO" otherwise. You can print each character either upper- or lowercase ("YeS" and "yes" are valid when the answer is "YES").

输入输出样例

输入样例 #1

1 3 2 1 2 1

输出样例 #1

YES

输入样例 #2

1 1 1 1 1 99

输出样例 #2

NO

说明

In the first sample, first team can be composed of $ 1 $ st, $ 2 $ nd and $ 6 $ th participant, second — of $ 3 $ rd, $ 4 $ th and $ 5 $ th: team scores are $ 1+3+1=2+1+2=5 $ . In the second sample, score of participant number $ 6 $ is too high: his team score will be definitely greater.