시간 제한 메모리 제한 제출 정답 맞은 사람 정답 비율
5 초 128 MB 21 12 12 60.000%

문제

Two positive integers are said to be coprime if 1 is their only common divisor. Given a sequence of positive integers a1, a2, ..., an, find the number of pairs of its terms which are coprime.

입력

The first line of input contains one integer n (1 ≤ n ≤ 1,000,000) denoting the length of the sequence. The second line contains n integers ai (1 ≤ ai ≤ 3,000,000).

출력

Your program should output one integer representing the number of pairs (i, j) such that 1 ≤ i < j ≤ n and ai is coprime with aj.

예제 입력

5
3 6 4 7 3

예제 출력

6

힌트

출처

Contest > Algorithmic Engagements > PA 2011 7-5번

  • 데이터를 추가한 사람: appa