CF982A Row

### 读入一个字符串，只含有$01$两种字符，合法则输出"$Yes$",否则输出"$No$"。 ### 不合法情况 $1$.一个为$0$的字符两旁没有$1$。 $2$.一个为$1$的字符两旁还有$1$。

共两行。第一行为一个正整数$n$，表示字符串的长度。第二行为一个字符串。

Output "Yes" (without quotation marks) if the seating is "maximal". Otherwise print "No". You are allowed to print letters in whatever case you'd like (uppercase or lowercase).

In sample case one the given seating is maximal. In sample case two the person at chair three has a neighbour to the right. In sample case three it is possible to seat yet another person into chair three.