CF1238A.Prime Subtraction

普及/提高-

通过率:0%

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题目描述

You are given two integers xx and yy (it is guaranteed that x>yx > y ). You may choose any prime integer pp and subtract it any number of times from xx . Is it possible to make xx equal to yy ?

Recall that a prime number is a positive integer that has exactly two positive divisors: 11 and this integer itself. The sequence of prime numbers starts with 22 , 33 , 55 , 77 , 1111 .

Your program should solve tt independent test cases.

输入格式

The first line contains one integer tt ( 1t10001 \le t \le 1000 ) — the number of test cases.

Then tt lines follow, each describing a test case. Each line contains two integers xx and yy ( 1y<x10181 \le y < x \le 10^{18} ).

输出格式

For each test case, print YES if it is possible to choose a prime number pp and subtract it any number of times from xx so that xx becomes equal to yy . Otherwise, print NO.

You may print every letter in any case you want (so, for example, the strings yEs, yes, Yes, and YES will all be recognized as positive answer).

输入输出样例

  • 输入#1

    4
    100 98
    42 32
    1000000000000000000 1
    41 40
    

    输出#1

    YES
    YES
    YES
    NO
    

说明/提示

In the first test of the example you may choose p=2p = 2 and subtract it once.

In the second test of the example you may choose p=5p = 5 and subtract it twice. Note that you cannot choose p=7p = 7 , subtract it, then choose p=3p = 3 and subtract it again.

In the third test of the example you may choose p=3p = 3 and subtract it 333333333333333333333333333333333333 times.

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