A dietitian arranges a special diet using three foods: L, M, and N. Each ounce of food L contains 28 units of calcium, 14 units of iron, 14 units of vitamin A, and 30 units of cholesterol. Each ounce of food M contains 14 units of calcium, 14 units of iron, 21 units of vitamin A, and 36 units of cholesterol. Each ounce of food N contains 14 units of calcium, 14 units of iron, 14 units of vitamin A, and 27 units of cholesterol. If the minimum daily requirements are 420 units of calcium, 280 units of iron, and 336 units of vitamin A, how many ounces of each food should be used to meet the minimum requirements and simultaneously minimize the cholesterol intake? What is the minimum cholesterol intake?