1 #include <set>
 2 #include <map>
 3 #include <queue>
 4 #include <cstdio>
 5 #include <string>
 6 #include <cstring>
 7 #include <cstdlib>
 8 #include <iostream>
 9 #include <algorithm>
10
11 typedef std::pair<std::string,int> pr;
12
13 int n;
14 int m;
15 int ans;
16 std::string from,to;
17 std::queue<pr> q1,q2;
18 std::string transform[10][2];
19 std::map<std::string,int> m1,m2;
20 std::pair<std::string,int> p1,p2;
21
22 bool Search();
23 void Initialize();
24 std::string Replace(std::string,int,int,std::string);
25
26 int main(){
27     Initialize();
28     if(Search())
29         std::cout<<ans<<std::endl;
30     else
31         std::cout<<"NO ANSWER!"<<std::endl;
32     return 0;
33 }
34
35 bool Search(){
36     int len,lenp;
37     while((!q1.empty())&&(!q2.empty())){
38         p1=q1.front();
39         len=p1.first.size();
40         for(int i=0;i<len;i++){
41             for(int j=0;j<m;j++){
42                 lenp=transform[j][0].size();
43                 if(i+lenp<=len&&p1.first.compare(i,lenp,transform[j][0])==0&&m1.count(Replace(p1.first,i,lenp,transform[j][1]))==0){
44                     p2.first=Replace(p1.first,i,lenp,transform[j][1]);
45                     p2.second=q1.front().second+1;
46                     if(p2.second>10)
47                         return false;
48                     m1[p2.first]=p2.second;
49                     q1.push(p2);
50                     if(m2.count(p2.first)){
51                         ans=p2.second+m2[p2.first];
52                         return true;
53                     }
54                 }
55             }
56         }
57         q1.pop();
58         p1=q2.front();
59         len=p1.first.size();
60         for(int i=0;i<len;i++){
61             for(int j=0;j<m;j++){
62                 lenp=transform[j][1].size();
63                 if(i+lenp<=len&&p1.first.compare(i,lenp,transform[j][1])==0&&m2.count(Replace(p1.first,i,lenp,transform[j][0]))==0){
64                     p2.first=Replace(p1.first,i,lenp,transform[j][0]);
65                     p2.second=q2.front().second+1;
66                     if(p2.second>10)
67                         return false;
68                     m2[p2.first]=p2.second;
69                     q2.push(p2);
70                     if(m1.count(p2.first)){
71                         ans=p2.second+m1[p2.first];
72                         return true;
73                     }
74                 }
75             }
76         }
77         q2.pop();
78     }
79     return false;
80 }
81
82 void Initialize(){
83     std::ios::sync_with_stdio(false);
84     std::cin.tie(0);
85     std::cin>>from>>to;
86     while(std::cin>>transform[m][0]>>transform[m][1])
87         m++;
88     m1[from]=0;
89     m2[to]=0;
90     q1.push(std::make_pair(from,0));
91     q2.push(std::make_pair(to,0));
92 }
93
94 inline std::string Replace(std::string s, int pos,int len,std::string p){
95     return s.replace(pos,len,p);
96 }