2017.08.25【NOIP提高组】模拟赛A组

1. 【NOIP2017提高A组模拟8.25】夜莺与玫瑰 (Standard IO)
   
   
   

Sample Input

4
2 2
7 10
23 34
100 100

Sample Output

6
1111
139395
22791174