m = int(input())
m1 = list(map(str,input().split()))
n = int(input())
s = 0
for i in range(m):
    if i == 0:
        if m1[i] == '0':
            if m1[1] == '0':
                s += 1
                m1[0] = '1'
    elif i == m-1:
        if m1[m-1] == '0':
            if m1[m-2] == '0':
                s += 1
                m1[m-1] = '1'
    else:
        if m1[i] == '0':
            if m1[i-1] == '0' and m1[i+1] == '0':
                s += 1
                m1[i] = '1'
if s >= n:
    print('true')
else:
    print('false')