program vahetamine;
var a, b, c: integer;
procedure vaheta;
begin;
 c:=a;
 a:=b;
 b:=c;
end;

begin
 a:=1;
 b:=3;
 writeln('a on ',a,' ja b on ',b);
 vaheta;
 writeln('N��d on a ',a,' ja b on ',b);
end.