RES
1b:a-dxyl-PEN-1:4
2r:r1
3b:a-dxyl-PEN-1:4
LIN
1:1o(3+5)2n
2:2n(3+5)3d
REP
REP1:4o(3+5)4d=-1--1
RES
4b:a-dxyl-PEN-1:4