Comparaison démographique et administrative : UK vs USA

Read the following facts about the UK and the USA and solve the problem.

Fact 1: The United Kingdom is composed of $4$ countries and has a population of approximately $67$ million inhabitants. It is located in Europe. Fact 2: The United States of America consists of $50$ states and has a population of approximately $333$ million inhabitants. It is located in North America.

Calculate the difference in population between the USA and the UK: $x = P_{USA} - P_{UK}$. Express the result in millions. Then, identify the total number of administrative regions (countries + states) for both territories combined: $y = 4 + 50$.