from sys import stdin

N = int(stdin.readline())

A = list(map(int,stdin.readline().split()))

ns = 0
ans = 0

for i in A:
    if i == 0:
        ans += ns * (ns+1)//2
        ns = 0
    else:
        ns += 1

ans += ns * (ns+1)//2

print (N*(N+1)//2-ans)