import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int[][] c = new int[3][3];
		int[] a = new int[3];
		int[] b = new int[3];
		boolean flag = false;

		for(int i = 0; i < 3; i++) {
			for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		}

		for(int i = 0; i <= 100; i++) {
			a[0] = i;
			b[0] = c[0][0] - i;
			b[1] = c[0][1] - i;
			b[2] = c[0][2] - i;
			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];
			flag = true;
			for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			}
			if(flag) break;
		}

		System.out.println(flag ? "Yes" : "No");
		sc.close();
	}
} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int[][] c = new int[3][3];
		int[] a = new int[3];
		int[] b = new int[3];
		boolean flag = false;

		for(int i = 0; i < 3; i++) {
			for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		}

		for(int i = 0; i <= 100; i++) {
			a[0] = i;
			b[0] = c[0][0] - i;
			b[1] = c[0][1] - i;
			b[2] = c[0][2] - i;
			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];
			flag = true;
			for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			}
			if(flag) break;
		}

		System.out.println(flag ? "Yes" : "No");
		sc.close();
	}
} Main public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int[][] c = new int[3][3];
		int[] a = new int[3];
		int[] b = new int[3];
		boolean flag = false;

		for(int i = 0; i < 3; i++) {
			for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		}

		for(int i = 0; i <= 100; i++) {
			a[0] = i;
			b[0] = c[0][0] - i;
			b[1] = c[0][1] - i;
			b[2] = c[0][2] - i;
			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];
			flag = true;
			for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			}
			if(flag) break;
		}

		System.out.println(flag ? "Yes" : "No");
		sc.close();
	} main {

		Scanner sc = new Scanner(System.in);
		int[][] c = new int[3][3];
		int[] a = new int[3];
		int[] b = new int[3];
		boolean flag = false;

		for(int i = 0; i < 3; i++) {
			for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		}

		for(int i = 0; i <= 100; i++) {
			a[0] = i;
			b[0] = c[0][0] - i;
			b[1] = c[0][1] - i;
			b[2] = c[0][2] - i;
			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];
			flag = true;
			for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			}
			if(flag) break;
		}

		System.out.println(flag ? "Yes" : "No");
		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int[][] c = new int[3][3]; c new int[3][3] 3 3 int[] a = new int[3]; a new int[3] 3 int[] b = new int[3]; b new int[3] 3 boolean flag = false; flag false for(int i = 0; i < 3; i++) {
			for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		} int i = 0; int i = 0; i 0 i < 3 i 3 i++ i++ i {
			for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		} {
			for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		} for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			} int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
				c[i][j] = sc.nextInt();
			} {
				c[i][j] = sc.nextInt();
			} c[i][j] = sc.nextInt() c[i][j] c[i] c i j sc.nextInt() sc.nextInt sc for(int i = 0; i <= 100; i++) {
			a[0] = i;
			b[0] = c[0][0] - i;
			b[1] = c[0][1] - i;
			b[2] = c[0][2] - i;
			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];
			flag = true;
			for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			}
			if(flag) break;
		} int i = 0; int i = 0; i 0 i <= 100 i 100 i++ i++ i {
			a[0] = i;
			b[0] = c[0][0] - i;
			b[1] = c[0][1] - i;
			b[2] = c[0][2] - i;
			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];
			flag = true;
			for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			}
			if(flag) break;
		} {
			a[0] = i;
			b[0] = c[0][0] - i;
			b[1] = c[0][1] - i;
			b[2] = c[0][2] - i;
			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];
			flag = true;
			for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			}
			if(flag) break;
		} a[0] = i a[0] a 0 i b[0] = c[0][0] - i b[0] b 0 c[0][0] - i c[0][0] c[0] c 0 0 i b[1] = c[0][1] - i b[1] b 1 c[0][1] - i c[0][1] c[0] c 0 1 i b[2] = c[0][2] - i b[2] b 2 c[0][2] - i c[0][2] c[0] c 0 2 i a[1] = c[1][0] - b[0] a[1] a 1 c[1][0] - b[0] c[1][0] c[1] c 1 0 b[0] b 0 a[2] = c[2][0] - b[0] a[2] a 2 c[2][0] - b[0] c[2][0] c[2] c 2 0 b[0] b 0 flag = true flag true for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			} int m = 0; int m = 0; m 0 m < 3 m 3 m++ m++ m {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			} {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			} for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				} int k = 0; int k = 0; k 0 k < 3 k 3 k++ k++ k {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				} {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				} if(c[m][k] != (a[m] + b[k])) flag = false; c[m][k] != (a[m] + b[k]) c[m][k] c[m] c m k (a[m] + b[k]) a[m] a m b[k] b k flag = false flag false if(flag) break; flag break; System.out.println(flag ? "Yes" : "No") System.out.println System.out System System.out flag ? "Yes" : "No" flag "Yes" "No" sc.close() sc.close sc String[] args args public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int[][] c = new int[3][3];
		int[] a = new int[3];
		int[] b = new int[3];
		boolean flag = false;

		for(int i = 0; i < 3; i++) {
			for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		}

		for(int i = 0; i <= 100; i++) {
			a[0] = i;
			b[0] = c[0][0] - i;
			b[1] = c[0][1] - i;
			b[2] = c[0][2] - i;
			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];
			flag = true;
			for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			}
			if(flag) break;
		}

		System.out.println(flag ? "Yes" : "No");
		sc.close();
	}
} public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int[][] c = new int[3][3];
		int[] a = new int[3];
		int[] b = new int[3];
		boolean flag = false;

		for(int i = 0; i < 3; i++) {
			for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		}

		for(int i = 0; i <= 100; i++) {
			a[0] = i;
			b[0] = c[0][0] - i;
			b[1] = c[0][1] - i;
			b[2] = c[0][2] - i;
			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];
			flag = true;
			for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			}
			if(flag) break;
		}

		System.out.println(flag ? "Yes" : "No");
		sc.close();
	}
} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int[][] c = new int[3][3];
		int[] a = new int[3];
		int[] b = new int[3];
		boolean flag = false;

		for(int i = 0; i < 3; i++) {
			for(int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		}

		for(int i = 0; i <= 100; i++) {
			a[0] = i;
			b[0] = c[0][0] - i;
			b[1] = c[0][1] - i;
			b[2] = c[0][2] - i;
			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];
			flag = true;
			for(int m = 0; m < 3; m++) {
				for(int k = 0; k < 3; k++) {
					if(c[m][k] != (a[m] + b[k])) flag = false;
				}
			}
			if(flag) break;
		}

		System.out.println(flag ? "Yes" : "No");
		sc.close();
	}
}