program ABC088C
    implicit none
    integer(8)::C(3,3),i,j,A(3)
    read*,C
    A(1)=C(1,1)+C(1,2)-2*C(1,3)
    A(2)=C(2,1)+C(2,2)-2*C(2,3)
    A(3)=C(3,1)+C(3,2)-2*C(3,3)
    if(A(1)==A(2).and.A(2)==A(3))then
        print'(A)',"Yes"
    else
        print'(A)',"No"
    end if
end program ABC088C