please use the letter C and follow the directions code using python

Write in Python: - A function ???, where ??? is the first letter of your family name, to do specific computation. (For example, to compute the length of a string) - A program to input data, call/execute function, and output result. The function may print/report only errors. The function should not print the computed value. The program: - Input/read input data - call and execute the appropriate function - output/print result(s)/output data The function(s) and program must be into two separate python files. The function(s) and program must be designed from the scratches. It is not allowed to use standard and library functions. A character is "a decimal digit", "an upper-case letter", or "a lower-case letter". A string a sequence of characters. A set is a collection of no duplicate elements. An element is a string