1 #include<bits/stdc++.h> 2 using namespace std; 3 typedef unsigned int ui; 4 typedef long long ll; 5 typedef unsigned long long ull; 6 #define pf printf 7 #define prime1 1e9+7 8 #define prime2 1e9+9 9 #define scand(x) scanf("%llf",&x) 10 #define f(i,a,b) for(int i=a;i<=b;i++) 11 #define scan(a) scanf("%d",&a) 12 #define dbg(args) cout<<#args<<":"<<args<<endl; 13 #define pb(i) push_back(i) 14 #define ppb(x) pop_back(x) 15 #define maxn 100005 16 int m,t,tot; 17 struct node{ 18 char st,ed; 19 }n[maxn]; 20 char s[maxn]; 21 bool vis[maxn]; 22 bool dfs(char a) 23 { 24 if(a=='m')return true; 25 f(i,0,tot-1) 26 { 27 if(n[i].st==a&&!vis[i]) 28 { 29 vis[i]=true; 30 if(dfs(n[i].ed))return true; 31 vis[i]=false; 32 } 33 } 34 return false; 35 } 36 int main() 37 { 38 std::ios::sync_with_stdio(false); 39 while(scanf("%s",s)==1) 40 { 41 if(strcmp(s,"0")==0) 42 { 43 if(dfs('b')) 44 { 45 pf("Yes. "); 46 } 47 else pf("No. "); 48 tot=0; 49 memset(vis,false,sizeof(vis)); 50 continue; 51 } 52 n[tot].st=s[0]; 53 n[tot].ed=s[strlen(s)-1]; 54 tot++; 55 } 56 }