시간 제한 | 메모리 제한 | 제출 | 정답 | 맞힌 사람 | 정답 비율 |
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2 초 | 128 MB | 28 | 15 | 12 | 52.174% |
At the latest KBTU ”Commencement” party Bakhytzhan noticed that there were n girls D1,D2,...,Dn and 2n−1 boys B1,B2,...,B2n−1. And every girl Dj knows exactly boys B1,B2,...,B2j−1. Throughout the evening party Bakhytzhan tried to count the number of possible choices of exactly r acquainted boys and girls pairs for dancing. That’s why he missed his chance for dancing. Please, write a program that would help Bakhytzhan don’t miss a chance to dance at the next party.
The input file contains two integer numbers n and r (1 ≤ n,r ≤ 106) separated by a space.
Output file should contain answer to Bakhytzhan’s problem – residue modulo 2946859
3 2
18
Contest > KBTU Open > KBTU Open 2008 K번