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 (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>

int main(){
	int c[9];
	int i;
	int flag=0;
	for(i=0;i<3;i++){
		scanf("%d%d%d",&c[3*i],&c[3*i+1],&c[3*i+2]);
	}
	
	if(c[0]-c[1]==c[3]-c[4] && c[0]-c[1]==c[6]-c[7] && c[1]-c[2]==c[4]-c[5] && c[1]-c[2]==c[7]-c[8] && c[0]-c[3]==c[1]-c[4] && c[0]-c[3]==c[2]-c[5] && c[3]-c[6]==c[4]-c[7] && c[3]-c[6]==c[5]-c[8]){
		flag=1;
	}
	if(flag==1){
		printf("Yes\n");
	}else{
		printf("No\n");
	}
	return 0;
}