Problem A

#this is a very simple and typical problem about how to deal with string,
#ut i haven't considered about the initial and end problem.
#so yeal, in initial or end point if '00' exists， it should output also
#'No', so i can just add '0' both in end and initial of the string and at
#the same time has no influence on others of the string.
#Also, we avoid the situation that len(a) == 1
def F(a):
a = '0' + a + '0'
if len(a) == 1:                   #this is no need
print('Yes')
return

else:
if a.find('11') == -1:

if a.find('000') == -1:
print('Yes')
return

print('No')
return
n = input()
a = str(input())
F(a)