N = int(input())
A = list(map(int, input().split()))
A.append(0)

all = N * (N + 1) // 2
N += 1


def search_one():
    a = 0
    b = len(A)
    while True:
        j = a + (b - a) // 2
        if '1' * j in A:
            a = j
        else:
            b = j
        if b - a < 3:
            break
    return b
onecnt = 0
now = 'zero'
for i in range(N):
    if A[i] == 1:
        if now == 'zero':
            cnt = 1
            now = 'one'
        else:
            cnt += 1
    else:
        if now == 'one':
            onecnt +=  (cnt * (cnt + 1) // 2)
            #print(i, cnt)
            now = 'zero'

print(all - onecnt)