so
soon
river
goes
them
got
moon
begin
big
0

Yes.

Hint
Hint
 
Harry 可以念这个咒语:"big-got-them".
#include<stdio.h>
#include<string.h>
struct node{
	char head,last;
}s[10000];
char ch[1000];
int vis[1000],i,flag;
void dfs(int x){
	if(s[x].last=='m')
		 flag=1;
	for(int k=0;k<i;k++){
		if(!vis[k] && s[k].head==s[x].last){
			vis[k]=1;
			dfs(k);
			vis[k]=0;//这不回溯居然都能过 
		}
	}
}
int main(){
	i=0;
	while(scanf("%s",ch)!=EOF){
		int len=strlen(ch);
		if(ch[0]!='0'){
			s[i].head=ch[0];
			s[i].last=ch[len-1];
			i++;
		}else{
			flag=0;
			memset(vis,0,sizeof(vis));
			for(int j=0;j<i;j++){
				if(s[j].head=='b'){
					vis[j]=1;
					dfs(j);
					if(flag)	
						break;
				}
			}
			if(flag) printf("Yes.\n");
			else printf("No.\n");
			i=0;
		}
	}
	return 0;
}