import sys
input = sys.stdin.readline

N=int(input())
A=list(map(int,input().split()))

S=[0]*N
for i in range(N-2,-1,-1):
    if A[i]==A[i+1]:
        S[i]=1
    else:
        S[i]=S[i+1]+1

ANS=0
for i in range(N):
    if A[i]==1:
        ANS+=S[i]

print(ANS)