Problem:
Score: 300 points

Problem Statement

We have a 3 \times 3 grid. A number c_{i, j} is written in the square (i, j), where (i, j) denotes the square at the i-th row from the top and the j-th column from the left.

According to Takahashi, there are six integers a_1, a_2, a_3, b_1, b_2, b_3 whose values are fixed, and the number written in the square (i, j) is equal to a_i + b_j.

Determine if he is correct.

Constraints

c_{i, j} \ (1 \leq i \leq 3, 1 \leq j \leq 3) is an integer between 0 and 100 (inclusive).

Input

Input is given from Standard Input in the following format:

c_{1,1} c_{1,2} c_{1,3}
c_{2,1} c_{2,2} c_{2,3}
c_{3,1} c_{3,2} c_{3,3}

Output

If Takahashi's statement is correct, print Yes; otherwise, print No.

Sample Input 1

1 0 1
2 1 2
1 0 1

Sample Output 1

Yes

Takahashi is correct, since there are possible sets of integers such as: a_1=0,a_2=1,a_3=0,b_1=1,b_2=0,b_3=1.

Sample Input 2

2 2 2
2 1 2
2 2 2

Sample Output 2

No

Takahashi is incorrect in this case.

Sample Input 3

0 8 8
0 8 8
0 8 8

Sample Output 3

Yes

Sample Input 4

1 8 6
2 9 7
0 7 7

Sample Output 4

No

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using static System.Console;
using static System.Int32;
using static System.Math;

class Program
{

    static void Main(string[] args)
    {
        label:
        WriteLine(hoge() ? "Yes" : "No");
    }

    static bool hoge()
    {
        var sp = ReadLine().Split();
        int n00 = Parse(sp[0]);
        int n01 = Parse(sp[1]);
        int n02 = Parse(sp[2]);
        sp = ReadLine().Split();
        int n10 = Parse(sp[0]);
        int n11 = Parse(sp[1]);
        int n12 = Parse(sp[2]);
        sp = ReadLine().Split();
        int n20 = Parse(sp[0]);
        int n21 = Parse(sp[1]);
        int n22 = Parse(sp[2]);
        if (n00 - n01 != n10 - n11) return false;
        if (n00 - n01 != n20 - n21) return false;
        if (n00 - n02 != n10 - n12) return false;
        if (n00 - n02 != n20 - n22) return false;
        if (n00 - n10 != n01 - n11) return false;
        if (n00 - n10 != n02 - n12) return false;
        if (n00 - n20 != n01 - n21) return false;
        if (n00 - n20 != n02 - n22) return false;
        return true;
    }
}