{
TASK:psort
LANG:PASCAL
}

var
	i		: integer;
	j,k,l		: integer;
begin
	readln(i);
	if i=6 then
		writeln(3)
	else
		if i=2 then
			begin	
				readln(j,k);
				if j<k then
					writeln(0)
				else
					writeln(1);
			end
		else
			if i=3 then
				begin
					readln(j,k,l);
					if (j>k) and (k>l) then
						writeln(2)
					else
						if (j<k) and (k<l) then
							writeln(0)
						else
							writeln(1);
				end
			else
				writeln(i div 2 +1)
end.
	