1800   IF V$="K" THEN GOTO 1800.2
1800.1 GOTO 1800.4
1800.2 A$="+K+"
1800.3 GOTO 1800.d
1800.4 IF V$="R" THEN GOTO 1800.6
1800.5 GOTO 1800.8
1800.6 A$="?R?"
1800.7 GOTO 1800.d
1800.8 IF V$="M" THEN GOTO 1800.a
1800.9 GOTO 1800.d
1800.a A$="!M!"
1800.b Z1=R1
1800.c Z2=R2
1800.d REM