class BIT:
    def __init__(self, n):
        self.n = n
        self.data = [0]*(n+1)

    def to_sum(self, i):
        s = 0
        while i > 0:
            s += self.data[i]
            i -= (i & -i)
        return s

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

    def get(self, i, j):
        return self.to_sum(j)-self.to_sum(i-1)


def count_inversion(lists):
    ans = 0
    N = len(lists)
    tree = BIT(N)
    for index, p in enumerate(lists):
        tree.add(p, 1)
        ans += index+1-tree.to_sum(p)
    return ans


N = int(input())
A = [int(input()) for i in range(N)]
ans = count_inversion(A)
print(ans)