1.
Let a,b,ca, b, c be such that b(a+c)0b(a+c) \ne 0. If
aa+1a1bb+1b1cc1c+1+a+1b+1c1a1b1c+1(1)n+2a(1)n+1b(1)nc=0\begin{vmatrix} a & a+1 & a-1 \\ -b & b+1 & b-1 \\ c & c-1 & c+1 \end{vmatrix} + \begin{vmatrix} a+1 & b+1 & c-1 \\ a-1 & b-1 & c+1 \\ (-1)^{n+2}a & (-1)^{n+1}b & (-1)^n c \end{vmatrix} = 0

then the value of nn is