n = int(input())
data = [0] * (n + 1)


def add(k, x):
    while k <= n:
        data[k] += x
        k += k & -k


def sum(k):
    s = 0
    while k:
        s += data[k]
        k -= k & -k
    return s


lis = list(map(int, input().split()))
res = 0
for i, j in enumerate(lis):
    add(j, 1)
    res += i + 1 - sum(j)
print(res)