1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<queue>
 5 #include<string>
 6 #include<algorithm>
 7 using namespace std;
 8 #define INF (1<<29)
 9 int n,G[222][222];
10 int d[222][10001];
11 bool vis[222][10001];
12 struct Node{
13     int u,mx;
14     Node(int _u,int _mx):u(_u),mx(_mx){}
15 };
16 void SPFA(int vs){
17     for(int i=0; i<n; ++i){
18         for(int j=0; j<10001; ++j) d[i][j]=INF;
19     }
20     d[vs][0]=0;
21     memset(vis,0,sizeof(vis));
22     vis[vs][0]=1;
23     queue<Node> que;
24     que.push(Node(vs,0));
25     while(!que.empty()){
26         Node nd=que.front(); que.pop();
27         int u=nd.u,mx=nd.mx;
28         for(int v=0; v<n; ++v){
29             if(G[u][v]==INF) continue;
30             if(G[u][v]>mx && d[v][G[u][v]]>d[u][mx]+mx){
31                 d[v][G[u][v]]=d[u][mx]+mx;
32                 if(!vis[v][G[u][v]]){
33                     vis[v][G[u][v]]=1;
34                     que.push(Node(v,G[u][v]));
35                 }
36             }
37             if(d[v][mx]>d[u][mx]+G[u][v]){
38                 d[v][mx]=d[u][mx]+G[u][v];
39                 if(!vis[v][mx]){
40                     vis[v][mx]=1;
41                     que.push(Node(v,mx));
42                 }
43             }
44         }
45         vis[u][mx]=0;
46     }
47 }
48 int main(){
49     string name[222],x[111],y[111],vs,vt;
50     int m,z[111];
51     while(cin>>vs>>vt){
52         n=0;
53         scanf("%d",&m);
54         for(int i=0; i<m; ++i){
55             cin>>x[i]>>y[i]>>z[i];
56             name[n++]=x[i]; name[n++]=y[i];
57         }
58         sort(name,name+n);
59         n=unique(name,name+n)-name;
60         for(int i=0; i<n; ++i){
61             for(int j=0; j<n; ++j) G[i][j]=INF;
62         }
63         for(int i=0; i<m; ++i){
64             int u=lower_bound(name,name+n,x[i])-name,v=lower_bound(name,name+n,y[i])-name;
65             G[u][v]=z[i];
66         }
67         SPFA(lower_bound(name,name+n,vs)-name);
68         int tv=lower_bound(name,name+n,vt)-name;
69         int res=INF;
70         for(int i=0; i<10001; ++i) res=min(res,d[tv][i]);
71         printf("%d\n",res);
72     }
73     return 0;
74 }