P8813 [CSP-J 2022] Exponentiation.

To simulate the scoring situation during a contest, the time limit of this problem is reduced by $50\%$.

Xiaowen has just started learning competitive programming. One day, she ran into this problem: given positive integers $a$ and $b$, find the value of $a^b$. Here, $a^b$ means multiplying $a$ by itself $b$ times. For example, $2^3$ means multiplying three $2$'s together, and the result is $2 \times 2 \times 2 = 8$. “So easy!” Xiaowen thought, and she quickly wrote a program. However, it produced an error during testing. Xiaowen soon realized that all variables in her program were of type `int`. On most machines, the largest number that `int` can represent is $2^{31} - 1$, so once the computed result exceeds this number, her program will fail. Since Xiaowen has just learned programming, she worries that using `int` might cause problems. Therefore, she wants you to output `-1` as a warning when the value of $a^b$ exceeds ${10}^9$; otherwise, output the correct value of $a^b$. However, Xiaowen still does not know how to implement this program, so she asks you for help.

The input consists of one line with two positive integers $a, b$.

Output one line: if $a^b$ does not exceed ${10}^9$, output $a^b$; otherwise output `-1`.

For $10\%$ of the testdata, it is guaranteed that $b = 1$. For $30\%$ of the testdata, it is guaranteed that $b \le 2$. For $60\%$ of the testdata, it is guaranteed that $b \le 30$, and $a^b \le {10}^{18}$. For $100\%$ of the testdata, it is guaranteed that $1 \le a, b \le {10}^9$. $\text{upd 2022.11.14/2025.04.02}$: One additional set of $\text{Hack}$ testdata has been added each time. Translated by ChatGPT 5