`input()` reads data entered by the user. The result of `input()` is initially a string. `int()` converts a numeric string into an integer. The `+` operator adds numbers. The `//` operator performs integer division and keeps the whole-number part. The `%` operator returns the remainder after division. `print()` displays the program result. Print only what the problem statement requires.

**Connection to this task.** The `//` and `%` operators complement each other: the first gives the integer quotient and the second gives the remainder. This is useful when splitting a number into groups or digits. The expression `a + b + c + d` shows how this idea is applied to the task data.