시간 제한메모리 제한제출정답맞힌 사람정답 비율
1 초 128 MB26881689156164.611%

문제

강민이 동생 희주는 올해 초등학교에 입학했다. 며칠 있으면, 생애 첫 시험을 보게 될텐데, 수학시험도 같이 본다고 한다.

희주는 겁을 먹은 나머지, 열심히 준비해야겠다고 생각했다. 이를 본 오빠 강민이는 동생 희주를 위해 작은 도움을 주고자 한다.

연습문제 중에 하나가 정수를 적어나가는 것이였는데 수열은 1이 한 개, 2가 두 개, 3이 세 개.. 와 같이 만들어진다.

이제 강민이는 희주에게 두 개의 정수 A, B를 부를텐데, 그럼 희주는 주어진 수열에서 A번째와 B번째 사이에 있는 모든 수들의 합을 말해야한다.

예를 들면, A가 1이고 B는 3이라면 답은 처음 세 개의 정수를 더한 1+2+2 = 5 가 된다.

희주에게 문제를 내기 위해 정답을 계산하는 프로그램을 작성하시오.

입력

한 줄에 양의 정수 A와 B가 주어진다. (1 ≤ A ≤ B ≤ 1000)

출력

희주가 대답해야 할 정답을 출력한다.

예제 입력 1

1 3

예제 출력 1

5

예제 입력 2

3 7

예제 출력 2

15

예제 입력 3

50 50

예제 출력 3

10
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출처

Olympiad > Croatian Highschool Competitions in Informatics > 2008 > Regional Competition - Juniors 1번

  • 문제를 번역한 사람: joonas
  • 잘못된 조건을 찾은 사람: tncks0121