MODULE zad1;
FROM Stek IMPORT Stack, MakeNull, Empty, Push, Top, Pop;
FROM FIO IMPORT RdStr, WrStr, WrLn, File, Create, Append, Open, Close ;
VAR
f:File;
ok,EOL,EOF: BOOLEAN;
str:ARRAY[1..20] OF CHAR;
stek1,stek2,stek3:Stack;

BEGIN
f:=Open('veliki.txt');
MakeNull(stek1);
MakeNull(stek2);
MakeNull(stek3);
WHILE NOT EOL DO
RdStr(f,str);
Push(stek1,str,ok);
END;
Close(f);
WHILE NOT Empty(stek1) DO
Top(stek1,str,ok);
Pop(stek1,ok);
Push(stek2,str,ok);
Top(stek1,str,ok);
Pop(stek1,ok);
Push(stek3,str,ok);
END;
f:=Create('mali1.txt');
f:=Append('mali1.txt');
WHILE NOT Empty(stek2) DO
Top(stek2,str,ok);
WrStr(f,str);
WrLn(f);
Pop(stek2,ok);
END;
Close(f);
f:=Create('mali2.txt');
f:=Append('mali2.txt');
WHILE NOT Empty(stek3) DO
Top(stek3,str,ok);
WrStr(f,str);
WrLn(f);
Pop(stek3,ok);
END;
Close(f);
END zad1.