class Bit:
    """1-indexed"""

    def __init__(self, n):
        self.size = n
        self.tree = [0] * (n + 1)

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

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


N = int(input())
M = tuple(map(int, input().split()))
bit = Bit(N)
ans = 0

for i, m in enumerate(M):
    bit.add(m, 1)
    ans += i + 1 - bit.sum(m)
print(ans)