def aa(s):
    d=1
    while s<len(fen):
        if s&d:
            fen[s]+=1
            s+=d
        d<<=1
def bb(s):
    res,d=0,1
    while s:
        if s&d:
            res+=fen[s]
            s-=d
        d<<=1
    return res


n=int(input())
fen=[0]*(n+1);ans=0
for i in range(n):
    c=int(input())
    ans+=i-bb(c)
    aa(c)
print(ans)