Computer Programming Contest Preparation

    1 1
    2 IF
    3 ELSE
    4 END_IF
    5 ENDPROGRAM
    6 IF
    7 ELSE
    8 END_IF
    9 IF
   10 ELSE
   11 END_IF
   12 IF
   13 ELSE
   14 END_IF
   15 IF
   16 ELSE
   17 END_IF
   18 IF
   19 ELSE
   20 END_IF
   21