m = int(input())
a = list(map(int, input().split()))
n = int(input())

count = 0
l = []

for i in a:
    if i == 0:
        count += 1
    else:
        if count >= 3:
            l.append(count)
        count = 0  # 不管怎样都要清零

# 最后一段连续的 0 也要判断
if count >= 3:
    l.append(count)

res = 0
for x in l:
    if x == 3:
        res += 1
    elif x > 3:
        res += (x - 3)//2 + 1

print('true' if res >= n else 'false')