20250716

# n = int((input()))
# arr=list(map(int,input().split()))
# e=1
# for i in range(len(arr)) :
#     e=i
#     for j in range(len(arr)) :
#         print("%d"%arr[e],end=' ')
#         if e==n-1 :
#             e=-1
#         e=e+1
#     print()


#
# e=0
# for i in range(len(arr)) :
#     e = i
#     for j in range(len(arr)) :
#         print(e,end=' ')
#         # print("%d"%arr[e],end=' ')
#         if e==n-1 :
#             e=1
#         e=e+1
#     print()


# for j in range(5):
#     print(j)
#     j=10
n = input((int()))
arr=list(map(int,input().split()))
e=0
c=0
for i in range(len(arr)) :
    if arr[i]==1 :
        if e != 0
        c=1
        e=e+1
    else :
        arr[i]==0 :
            e=0
            continue