The best way to write a program is to immediately type in some code and then debug it until it works. An algorithm can be written without using a programming language. Programs no longer require modification after they are written and debugged. Python identifiers must start with a letter or underscore. Keywords make good variable names. Expressions are built from literals, variables, and operators. In Python, x - x + 1 is a legal statement. Python does not allow the input of multiple values with a single statement. A counted loop is designed to iterate a specific number of times. In a flowchart, diamonds are used to show statements, and rectangles are used for decision points.