Nobita punishment

Nobita is always late in his class. His teacher warned that if he is late again, he will punish him by making him run around the football field.But Nobita has a special friend Doraeman who has some special gadgets. To help Nobita, Doraemon gives him a special energy drink which will allow him to run m meters for each energy drink bottle. But Nobita does not knows how many such bottles will be need