A discrete time linear shift - invariant system has an impulse response h [n] with h [0] = 1, h [1] = - 1, h [2] = 2 and zero otherwise. The system is given an input sequence x [n] with x [0] = x [2] = 1 and zero otherwise. The number of non zero samples in the output sequence y [n] and the value of y [2] are respectively