Pooja is making punch for a winter party in a punch bowl that can hold at most 9 quarts. She wants to get as much vitamin C in her punch as possible, so she is suing only orange juice and grape juice. She has 6 quarts of orange juice, which has 2 grams of vitamin C per quart and 7 quarts of grape juice, which has 1 gram of vitamin C per quart. If there are 4 cups in a quart, what is the maximum amount of vitamin C, in grams, that Pooja can have in one cup of her punch?