import sys
input = sys.stdin.readline

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

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

count=0
for a in A:
    if a!=0:
        count+=1
    else:
        ANS-=count*(count+1)//2
        count=0

ANS-=count*(count+1)//2

print(ANS)