Prefixed expression (1)

Write a program that reads a prefixed expression, and prints the result of evaluating it. The three possible operators are sum, substraction and multiplication. The operands are natural numbers between 0 and 9 (both included).

Input

Input has a prefixed expression. This means that operators always appear before their operands. For instance, the expression $4 + 3$ would be written

+ 4 3

The expression $8 * (4 + 3)$ would be written

* 8 + 4 3

The expression $(2 - 8) * (4 + 3)$ would be written

* - 2 8 + 4 3

Output

Print a line with an integer number: the result of evaluating the given expression.

Hint

Note that an expression is either a digit or an operator, followed by an expression, followed by another expression. Take inspiration in this fact to write a simple recursive program.

Problem information

Author: Unknown
Translator: Salvador Roura

Generation: 2026-01-25T10:07:21.402Z