class Bit:
    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
def inversion(L):
    #座圧パート
    N=len(L)
    s=sorted(list(set(L)))
    M=len(s)
    d={ }
    for i,x in enumerate(s):
        d[x]=i+1
    #BITパート
    cnt=0
    bit=Bit(M)
    for i in range(N):
        bit.add(d[L[i]],1)
        cnt+=bit.sum(M)-bit.sum(d[L[i]])
    return cnt
n=int(input())
a=[int(input()) for _ in range(n)]
print(inversion(a))