Any mamas wanna help me calculate this ish

Okay so this is probably so simple but for the life of me I can't figure it out. I have to take extra folic acid pills(prescription) well my dr said I could buy some from Walmart instead of buying my prescription. So right now I take four 1MG tablets. This new bottle is 400MCG each tablet. How many from the new bottle do I take to match up what I already take?

***note: from what I've read online. MCG and MG are NOT the same thing, one is Milligram and the other MicroMilligram***