From [wu : riddles]

A patient has fallen very ill and has been advised to take exactly one pill of medicine X and exactly one pill of medicine Y each day, lest he die from either illness or overdosage. These pills must be taken together. The patient has bottles of X pills and Y pills. He puts one of the X pills in his hand. Then while tilting the bottle of Y pills, two Y pills accidentally fall out. Now there are three pills in his hand. Because both types of pill look identical, he cannot tell which two pills are type Y and which is type X. Since the pills are extremely expensive, the patient does not wish to throw away the ones in his hand. How can he save the pills in his hand and still maintain a proper daily dosage?