from itertools import groupby


n = int(input())
a = list(map(int, input().split()))
a.sort()
a = [(k, len(list(v))) for k, v in groupby(a)]
sum_cnt = 0
sm = 0
cnt = [0]
lst = [0]
ans = 0
for k, c in a:
    ans += c * (c - 1) // 2 * sm
    if 2 * lst[-1] > k:
        ok = len(lst) - 1
        ng = 0
        while (ok - ng) > 1:
            mid = (ok + ng) // 2
            if lst[mid] * 2 > k:
                ok = mid
            else:
                ng = mid
        ans += (sum_cnt - cnt[ng]) * c

    sum_cnt += c * (c - 1) // 2
    sm += c
    cnt.append(sum_cnt)
    lst.append(k)

print(ans)