互质 - Problème

#11254. 互质

Statistiques

AI Translation — This statement was translated using AI and may contain inaccuracies. Please refer to the original statement if in doubt.

给定两个正整数 $x$ 和 $y$，你的任务是找到一个满足以下条件的正整数 $z$：

$x < z < y$。
$\gcd(z, y) = 1$ 且 $\gcd(z, x) = 1$。

如果存在多个答案，你可以输出其中任意一个。如果不存在合法的 $z$，输出 $-1$。

输入格式

第一行包含测试用例的数量 $T$ ($1 \le T \le 10^4$)。

对于每个测试用例：第一行包含两个整数 $x$ 和 $y$ ($1 \le x, y \le 10^{10}, x + 2 \le y$)。

输出格式

对于每个测试用例，如果答案存在，请在一行中输出你的答案。否则，输出 $-1$。

样例

样例输入 1

样例输出 1

2
117
-1

Discussions

About Discussions

The discussion section is only for posting: General Discussions (problem-solving strategies, alternative approaches), and Off-topic conversations.

This is NOT for reporting issues! If you want to report bugs or errors, please use the Issues section below.

Open Discussions 0

No discussions in this category.

Issues

About Issues

If you find any issues with the problem (statement, scoring, time/memory limits, test cases, etc.), you may submit an issue here. A problem moderator will review your issue.

Guidelines:

This is not a place to publish discussions, editorials, or requests to debug your code. Issues are only visible to you and problem moderators.
Do not submit duplicated issues.
Issues must be filed in English or Chinese only.

Active Issues 0

No issues in this category.

Closed/Resolved Issues 0