Reverse Polish notation

Evaluate arithmetic expressions given in the so-called reverse Polish notation. For instance, the expression $3 + 154$ in reverse Polish notation is given as $3 \enspace 154 \enspace +$ That is, the two operands are given first, and afterwards comes the corresponding operator. A more complicated expression like

$((3 + 4) * (2 - 8)) + (2 + 5)$ is given as

$3 \enspace 4 \enspace + \enspace 2 \enspace 8 \enspace - \enspace * \enspace 2 \enspace 5 \enspace + \enspace +$

Input

Input consists of several arithmetic expressions in reverse Polish notation, one per line. The operands are natural numbers. The possible operators, all binary, are ‘+’, ‘-’, and ‘’.

Output

For every expression, print the result of its evaluation.

Problem information

Author: Unknown
Translator: Carlos Molina

Generation: 2026-01-25T11:08:41.547Z