Python 3 on my Android phone.
People get really scared of functions when they're first learning them but really, functions are easy. To use a function, you simply type the name of the function followed by parentheses, open then closed, in your code. Inside the parentheses, you put the day that you want to feed to the function.
There are only three lines of code in this program. The first one is the import statement, which imports the sys library. The second one is the print function. The function contains the string of characters inside the parentheses that you want to print to the standard output, in this case, the screen. Notice the characters are enclosed in double quotes. The third one is the exit function from the sys library. This function terminates the program.