var
m,n:integer;
begin
writeln('Vvedite kol-vo etazhei');
readln(n);
writeln('Kakoi nomer kvartiry?');
readln(m);
if m<=n*3 then
begin
n:=(m div 3);
if n mod 2 = 0 then m:=n-1
else m:=n;
if m=-1 then m:=1;
writeln('Lift ostanovitsya na ',m,' etazhe');
end else
writeln('neverno ukazan etazh');
readln;
end.