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21687_Abundance

2022-5-16 18:20| 发布者: Hocassian| 查看: 22| 评论: 0|原作者: 肇庆学院ACM合集

摘要:

C:\Users\Administrator\Downloads\2019-10-12-10-14-4-89505761150400-Problem List-采集的数据-后羿采集器.html

Pro.ID

21687

Title

Abundance

Title链接

http://10.20.2.8/oj/exercise/problem?problem_id=21687

AC

Submit

Ratio

100.00%

时间&空间限制

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)

描述

An abundant number is a positive integer n for which Sigma(n) - 2n > 0, Where Sigma(n) is defined as the sum of all the divisors of n. And the quantity Sigma(n) - 2n is called abundance.

Given the range of n, you should find out the maximum abundance value that can be reached. For example, if the range is [10, 12], then the only abundant number is 12, and the maximum abundance value is Sigma(12) - 2*12 = 4.

输入

Input may contain several test cases. The first line is a positive integer, T ( T ≤ 20 ), the number of test cases below. Each test case contains two positive integers x, y, ( 1 ≤ x ≤ y ≤ 1024 ), indicating the range of n.

输出

Description

An abundant number is a positive integer n for which Sigma(n) - 2n > 0, Where Sigma(n) is defined as the sum of all the divisors of n. And the quantity Sigma(n) - 2n is called abundance.

Input

Output

For each test case, output the maximum abundance value that can be reached in the range of n. If there is no abundant number n in the given range, simply output -1.

Sample Input

3
1 1
10 12
1 1024

Sample Output

-1
4
1208

Source

GDCPC 2006