global tree
global n,rank
def lowbit(x):
return x&(-x)
def query(x):
ans=0
while x:
ans+=tree[x]
x-=lowbit(x)
return ans
def add(index,k):
while index<=n:
tree[index]+=k
index+=lowbit(index)
n=int(input())
tree=[0]*(n+1)
rank=[0]*(n+1)
arr=[0]*(n+1)
arr[0]=[-float("inf"),-float("inf")]
msg=list(map(int,input().split()))
for i in range(n):
arr[i+1]=[i+1,msg[i]]
arr.sort(key=lambda x:x[1])
for i in range(1,n+1):
rank[arr[i][0]]=i
ans=0
for i in range(1,n+1):
add(rank[i],1)
ans+=(i-query(rank[i]))
print(ans)