hdu 3972 1 M possible 从3*n+2中找出两个特殊的数 (其余3*n每三个相同)

Problem Description

There are 3*N+2 nonnegative integers. Except two special integers, the rest 3*N integers can form N triple groups: { Vi, Vj, Vk| Vi=Vj=Vk}, each integer are at most in one triple group. There are 3*N+