 a =  0     0     0     0    00    00    00    00    00    00    00    00  0     0     0     0     0     0     0     0     0     0     0     0  0     0     0     0     0     0     0     0     0    00    00    00  0     0     0     0     0     0     0     0     0     0     0     0  