시간 제한메모리 제한제출정답맞힌 사람정답 비율
1 초 512 MB23601403117660.153%

문제

유니스트 컴퓨터공학과에 다니는 서윤이는 이번에 어떤 과목을 들을지 고민중이다. 학점을 잘 받을 수 있으면서도 중요한 과목을 듣고 싶은 서윤이는 모든 과목의 중요도와, 일정 이상의 학점을 받기 위해 필요한 공부시간을 다 적었다.

처음에는 모든 과목을 들으려고 했던 서윤이는 자신의 공부 시간에 한계가 있다는 것을 깨달았다. 그래서, 공부 시간의 한계를 초과하지 않으면서 과목의 중요도 합이 최대가 되도록 몇 개만 선택하여 수강하기로 마음먹었다.

중요도가 최대가 되도록 과목을 선택했을 때, 최대가 되는 중요도를 출력하는 프로그램을 작성하시오.

입력

첫줄에 서윤이의 최대 공부시간 N (1 ≤ N ≤ 10,000), 과목 수 K (1 ≤ K ≤ 1,000)이 공백을 사이에 두고 주어진다. 

이후 K개의 줄에 중요도 I (1 ≤ I ≤ 100,000), 필요한 공부시간 (1 ≤ T ≤ 10,000)이 공백을 사이에 두고 주어진다. 

출력

얻을 수 있는 최대 중요도를 출력한다.

예제 입력 1

80 3
650 40
700 60
60 40

예제 출력 1

710
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