1 #include<iostream>
2 #include<cstdio>
3 #include<algorithm>
4 #include<cstring>
5 #include<cmath>
6 #include<queue>
7 #include<vector>
8 #include<map>
9 #include<set>
10 #include<stack>
11 using namespace std;
12 int read(){
13 int x=0,f=1;char s=getchar();
14 while(s<'0'||s>'9'){if(s=='-') f=-1;s=getchar();}
15 while(s>='0'&&s<='9'){x=x*10+s-'0';s=getchar();}
16 return x*f;
17 }
18 queue<int>q;
19 const int maxn=1007;
20 const int maxm=20007;
21 const int INF=0x7f7f7f7f;
22 int n,ml,md,num;
23 int head[maxn],cnt[maxn],d[maxn];
24 bool flag;
25 bool inq[maxn];
26 struct Edge{
27 int nxt,to,dis;
28 }edge[maxm<<1];
29 void add(int from,int to,int dis){
30 edge[++num].nxt=head[from];
31 edge[num].to=to;
32 edge[num].dis=dis;
33 head[from]=num;
34 }
35 void spfa(int x){
36 memset(inq,false,sizeof(inq));
37 memset(d,INF,sizeof(d));
38 memset(cnt,0,sizeof(cnt));
39 d[x]=0;inq[x]=true;q.push(x);
40 while(!q.empty()){
41 int u=q.front();inq[u]=false;q.pop();
42 for(int i=head[u];i;i=edge[i].nxt){
43 int v=edge[i].to;
44 if(d[v]>d[u]+edge[i].dis){
45 d[v]=d[u]+edge[i].dis;
46 if(!inq[v]){
47 cnt[v]++;inq[v]=true;q.push(v);
48 if(cnt[v]>n){
49 cout<<-1<<endl;flag=true;return;
50 }
51 }
52 }
53 }
54 }
55 }
56 int main(){
57 //freopen("a.in","r",stdin);
58 n=read();ml=read();md=read();
59 for(int i=1;i<=ml;i++){
60 int u,v,w;u=read();v=read();w=read();
61 add(u,v,w);
62 }
63 for(int i=1;i<=md;i++){
64 int u,v,w;u=read();v=read();w=read();
65 add(v,u,-w);
66 }
67 for(int i=1;i<=n;i++) add(0,i,0);
68 for(int i=2;i<=n;i++) add(i,i-1,0);
69 spfa(0);
70 if(!flag){
71 spfa(1);
72 if(d[n]==INF) cout<<-2<<endl;
73 else cout<<d[n]<<endl;
74 }
75 return 0;
76 }
