N = int(input())
A = list(map(int,input().split()))
B = [0 for _ in range(N)]
cnt = 0
bef = -1
for i in reversed(range(N-1)):
    if A[i] != bef:
        bef = A[i]
        cnt += 1
        B[i] = cnt
    else:
        bef = A[i]
        cnt = 1
        B[i] = cnt
ans = 0
for i in range(N):
    if A[i] == 1 and i != N-1:
        ans += B[i]
print(ans)