1 array 1 1 2 var 1 3 var 1 4 var 1 5 var 1 6 write 1 1 1 2 3 7 read 1 6 4 8 read 1 6 5 9 eq 1 4 5 10 eq 1 7 8 11 and 1 9 -10 12 write 1 1 6 2 3 13 read 1 12 4 14 read 1 12 5 15 eq 1 13 14 16 and 1 9 -15 17 and 1 -11 -16 18 root 1 -17