`input()` reads data entered by the user. The result of `input()` is initially a string. `int()` converts a numeric string into an integer. `split()` separates one input line into individual values using spaces. The `+` operator adds numbers. The `-` operator subtracts one number from another. The `*` operator multiplies numbers. The `/` operator performs regular division and may return a decimal number. The `//` operator performs integer division and keeps the whole-number part. The `%` operator returns the remainder after division. Comparison operators `==`, `!=`, `<`, `>`, `<=`, `>=` compare values and produce `True` or `False`. `and` requires all combined conditions to be true. `or` requires at least one condition to be true. `if` checks a condition and runs its block when the condition is true. `else` runs when the corresponding `if` condition is false. `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 `'ERROR'` shows how this idea is applied to the task data.