N = int(input())
P = list(map(int,input().split()))
k = 0
while 2**k<N:
    k += 1
M = 2**k
T = [0]*(M+1)
def update(i,x):
    while i<=M:
        T[i] += x
        i += i&(-i)
def cumsum(i):
    tot = 0
    while i>0:
        tot += T[i]
        i -= i&(-i)
    return tot
ans = 0
for i in range(N):
    update(P[i],1)
    ans += i+1-cumsum(P[i])
print(ans)