import math
def f(n):
    if n < 2:
        return n
    else:
        return n * (n + 1) // 2

n = int(input())
a = list(map(int,input().split()))
c = []
cnt = 0
for i in range(n):
    if a[i] == 0:
        c.append(cnt)
        cnt = 0
    else:
        cnt += 1
c.append(cnt)

ans = f(n)
for i in c:
    ans -= f(i)
print(ans)