10
20 INPUT?79
30 MODE5:VDU28;31,19,8
40 !80=&5800:!84=&6901
50 A%=&7F:X%=79:Y%=0:CALL&FFF1
60 FORt%=0TO39
70 !80=&5800:!84=&5703:?86=t%
80 !88=&1E2A:CALL&FFF1:z%=?(?84+86)
90 IFz%AND&5FTHEN!84=&FF067D01:CALL&FFF1:PRINT~t%",";~?(?84+86)" = ";~z%
100 NEXT