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

    def add(self, p, x):  # pは0-indexed
        assert 0 <= p < self._n
        p += 1
        while p <= self._n:
            self.data[p] += x
            p += p & -p

    def sum_range(self, l, r):  # l,rは0-indexedで閉区間[l,r]の区間和を求める
        assert 0 <= l <= r <= self._n
        return self._sum(r+1)-self._sum(l)

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

    def lower_bound(self, x):  # a0+a1+...+ai>=xなるiのminを求める(0-indexed)
        lo = 1
        hi = self._n
        ret = 1 << 60
        while lo <= hi:
            m = (lo+hi)//2
            if self._sum(m) >= x:
                ret = min(ret, m)
                hi = m-1
            else:
                lo = m+1
        return ret-1


N = int(input())
M = [int(input())-1 for _ in range(N)]
B = BIT(N)
ans = 0
for i in range(N):
    num = B.sum_range(0, M[i])
    ans += i-num
    B.add(M[i], 1)
print(ans)