Codeforces (c) Copyright 2010-2017 Mike Mirzayanov The only programming contests Web 2.0 platform Server time: Sep/23/2017 13:40:37 UTC+9 (c3). Desktop version, switch to mobile version. lydrainbowcat | Logout | HOME CONTESTS GYM PROBLEMSET GROUPS RATING API CALENDAR Codeforces Round #313 (Div. 1) Finished Practice Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ACM-ICPC mode for virtual contests. If you've seen these problems, a virtual contest is not for you - solve these problems in the archive. If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive. Never use someone else's code, read the tutorials or communicate with other person during a virtual contest. Start virtual contest → Virtual participation Choose file: 浏览... Be careful: there is 50 points penalty for submission which fails the pretests or resubmission (except failure on the first test, denial of judgement or similar verdicts). "Passed pretests" submission verdict doesn't guarantee that the solution is absolutely correct and it will pass system tests. → Submit? Submit Submission Time Verdict 12176781 Jul/22/2015 18:10 Accepted 12176038 Jul/22/2015 18:05 Runtime error on pretest 4 → Last submissions No tag edit access → Problem tags combinatorics dp math number theory • Announcement #1 • Announcement #2 • Tutorial → Contest materials C. Gerald and Giant Chess time limit per test: 2 seconds memory limit per test: 256 megabytes input: standard input output: standard output Giant chess is quite common in Geraldion. We will not delve into the rules of the game, we'll just say that the game takes place on an h × w field, and it is painted in two colors, but not like in chess. Almost all cells of the field are white and only some of them are black. Currently Gerald is finishing a game of giant chess against his friend Pollard. Gerald has almost won, and the only thing he needs to win is to bring the pawn from the upper left corner of the board, where it is now standing, to the lower right corner. Gerald is so confident of victory that he became interested, in how many ways can he win? The pawn, which Gerald has got left can go in two ways: one cell down or one cell to the right. In addition, it can not go to the black cells, otherwise the Gerald still loses. There are no other pawns or pieces left on the field, so that, according to the rules of giant chess Gerald moves his pawn until the game is over, and Pollard is just watching this process. Input The first line of the input contains three integers: h, w, n — the sides of the board and the number of black cells (1 ≤ h, w ≤ 10 , 1 ≤ n ≤ 2000). Next n lines contain the description of black cells. The i-th of these lines contains numbers r , c (1 ≤ r  ≤ h, 1 ≤ c  ≤ w) — the number of the row and column of the i-th cell. It is guaranteed that the upper left and lower right cell are white and all cells in the description are distinct. Output Print a single line — the remainder of the number of ways to move Gerald's pawn from the upper left to the lower right corner modulo 10  + 7. Examples input 3 4 2 2 2 2 3 input 100 100 3 15 16 16 15 99 88 5 i i i i 9 output 2 output 545732279 PROBLEMS SUBMIT STATUS STANDINGS CUSTOM TEST Privacy Policy