print((function (f, g, n, s)
	return f(g(n,s))
end)(function (n)
	return (n==math.floor(n) and "%.0f" or "%.1f"):format(n)
end, function (n, s)
	local a,rs={},bit.rshift
	for e in s:gmatch("%-?%d+") do table.insert(a,tonumber(e)) end
	table.sort(a)
	if n==1 then return a[1] end
	if n%2~=0 then return a[rs(n,1)+1] end
	return (a[rs(n,1)]+a[rs(n,1)+1])/2
end, tonumber(io.stdin:read("*l")), io.stdin:read("*l")))