ACTIV - Activities

Ana likes many activities. She likes acrobatics, alchemy, archery, art, Arabic dances, and many more. She joined a club that offers several classes. Each class has a time interval in every week. Ana wants to sign up for many classes, but since they overlap in time, she looks for a subset of non-overlapping classes to attend. A subset is non-overlapping if it does not contain two classes that overlap in time. If a class starts at the time another class ends, this is not considered overlapping.

Ana decided to list all the non-overlapping non-empty subsets of classes. Then she will choose the subset she likes best. In order to predict the amount of paper needed to write the list, she wants you to calculate how many of these subsets there are.

Input

Each test case is described using several lines. The first line contains an integer N indicating the number of classes the club offers (1 ≤ N ≤ 105). Each of the next N lines describes a class using two integers S and E that represent the starting and ending times of the class, respectively (1 ≤ S < E ≤ 109). The end of input is indicated with a line containing a single −1.

Output

For each test case, output a single line with a single integer representing the number of non-overlapping non-empty subsets of classes. To make your life easier, output only the last 8 digits of the result. If the result has less than 8 digits, write it with leading zeros to complete 8 digits.

Example

Input: 
5
1 3
3 5
5 7
2 4
4 6
3
500000000 1000000000
1 500000000
1 500000000
1
999999999 1000000000
-1

Output: 
00000012
00000005
00000001

Added by:Pablo Ariel Heiber
Date:2010-09-24
Time limit:2.365s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64 NODEJS OBJC VB.NET
Resource:FCEyN UBA ICPC Selection 2010

hide comments
2016-07-16 21:39:08
easy one! basic dp + binary search. just take care of MOD ;)

Last edit: 2016-07-16 21:40:11
2015-07-21 19:06:26 Ravi kumar
dp+bit :)
2015-06-25 17:36:02 vivek singh rana
test case-
6
1 2
2 3
3 4
1 8
4 5
5 6
-1

ans-00000032
2015-05-29 13:00:25 Shubham
easy one silly mistake caused me so many WA......keep in mind ans will have 8 digits so dp value must be kept under 10^8 by taking mod :)
2015-01-17 21:59:13 Anmol Pandey
Nice Problem.
NlogN+Nlong passes
2014-05-29 20:50:23 Rishav Goyal
sorting reverse made me 3 WA's :/
2013-08-10 13:22:13 Bidhan
Time limit is ok, my solution is quite slow but gets accepted.

edit : my solution's complexity is O ( NlogN + NlogN )

Last edit: 2013-08-10 13:23:35
2013-06-03 01:02:35 nagato
even nlongn+nlogn giving TLE...:(
2012-06-05 16:27:48 Romal Thoppilan
Hey help me out with submission ID 7095149
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