1 array 1 1 
2 var 1
3 var 1
4 and 1 2 3
5 read 1 1 4
6 var 1
7 var 1
8 and 1 6 7
9 read 1 1 -8
10 eq 1 4 8
11 eq 1 5 9
12 implies 1 10 11
13 root 1 -12