Problem M. Escape
时间限制 2000 ms
内存限制 64 MB
2012 If this is the end of the world how to do? I do not know how. But now scientists have found that some stars, who can live, but some people do not fit to live some of the planet. Now scientists want your help, is to determine what all of people can live in these planets.
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输出数据
Determine whether all people can live up to these stars
If you can output YES, otherwise output NO.
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1 1
1
1
2 2
1 0
1 0
1 1
样例输出
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