题目描述
The educational program (AHK Education) of the Aiz Broadcasting Corporation broadcasts a program called "Play with Tsukuro" for children. Today is the time to make a box with drawing paper, but I would like to see if the rectangular drawing paper I prepared can make a rectangular parallelepiped. However, do not cut or fold the drawing paper.
Given six rectangles, write a program to determine if you can make a rectangular parallelepiped using them.
Input
The input is given in the following format.
h1 w1
h2 w2
h3 w3
h4 w4
h5 w5
h6 w6
The input consists of 6 lines, each line given the integer hi (1 ≤ hi ≤ 1000) for the vertical length of each rectangle and the integer wi (1 ≤ wi ≤ 1000) for the horizontal length.
Output
If a rectangular parallelepiped can be created, "yes" is output, and if it cannot be created, "no" is output. However, since a cube is a kind of rectangular parallelepiped, "yes" is output even if it is a cube.
Examples
Input
2 2
2 3
2 3
2 3
2 2
3 2
Output
yes
Input
2 2
2 3
2 3
2 3
2 2
2 2
Output
no
输入格式
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输出格式
见题面