Consider the following classifications of age, height, sex, and weight. An age is any whole number from 0 to 100, inclusive. A height is any expression of the form a feet, b inches where a and b are whole numbers and all heights ranges from the smallest assumed height of 1 foot, 0 inches to the largest assumed height of 8 feet, 0 inches. A sex is either male or female. A weight is any whole number from 5 pounds to 400 pounds, inclusive. Assuming that there are 320 million people living in the United States today, what minimum number of these is guaranteed to have the same age, height, sex, and weight?