Chef and Inflation

A recent glut in Chefland's markets has caused the local currency Peppercorn to devaluate sharply. (Peppercorns are getting cheaper on an average, though there could be ups and downs). And Chef needs to rescue his wealth! Initially, he had D Peppercorns. There are N exchange kiosks in the city he lives in, where he can go and exchange his Peppercorns for a well-known stable currency, the Antarcti