A camera is to be used primarily in 587 nm yellow light. What is the second thinnest lens coating of magnesium fluoride that would be non-reflective for the yellow light? Assume that the incident light is approximately perpendicular to the lens surface and take the index of refraction to be 1.00 for air, 1.38 for magnesium fluoride, and 1.52 for the lens glass. Report your answer in units of nm.