1 var 1
2 var 4
3 var 4
4 var 4

5 urem 4 2 3 
6 urem 4 2 4
7 cond 4 1 5 6
8 cond 4 1 3 4
9 urem 4 2 8

10 eq 1 7 9

11 urem 4 2 4
12 urem 4 3 4
13 cond 4 1 11 12
14 cond 4 1 2 3
15 urem 4 14 4

16 eq 1 13 15

17 or 1 -10 -16 
18 root 1 17