print((function (f)
	local a,b,c = f()
	while a~=0 do a,b,c = a/2,b+a/2,a+a>c and a+a or c end
	return tonumber(b-c<0 and c-b or b-c)
end)((function (ffi)
	ffi.cdef 'int scanf(const char *, ...);'
	local C,c = ffi.C,ffi.new("long[1]")
	return function () C.scanf("%ld",c) return c[0],c[0],c[0] end
end)(require'ffi')))