Write an algorithm and flowchart of the following program:

You are tasked with writing a program that calculates the total bill for a customer's purchase. The program should perform the following steps: Prompt the user to enter the prices of three items $($item$1,$ item$2,$ and item$3).$ Calculate the subtotal and add a $10\%$ VAT to the total. If the total bill $($including VAT$)$ is more than $500,$ apply a $50$ TK discount. Print the total bill after applying the VAT and discount.