[x77]
; x77 - number of entries
FR
?Selection doc file?          
; <1>
FR
?Odd selection doc file?      
; <2>
FR
?Even selection doc file?     
; <3>
;
X78=1
; prepare document files
DO LB21 i=x78,x77
SD x0,x0
<1>
lb21
SD E
<1>
;
x21=-1
x22=0
DO lb22 i=x78,x77
IF(x21.gt.0.0) goto lb23
x22=x22+1
SD x22,x0
<3>
x21=-x21
GOTO lb22
LB23
SD x22,x0
<2>
x21=-x21
LB22 
SD E
<2>
SD E
<3>
;
RE