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

ans = n * (n+1) // 2
cnt = 0
for a in A:
    if a != 0:
        cnt += 1
    else:
        ans -= cnt * (cnt + 1) // 2
        cnt = 0
ans -= cnt * (cnt + 1) // 2
print(ans)