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

ans = 0
ct = 0
B = [0]*N
r = 0
for i in range(N):
    while r < N and (i == r or A[r-1] != A[r]):
        r += 1
    B[i] = r

for i in range(N-1):
    if A[i]:
        ans += B[i]-i-(B[i] == N)

print(ans)