> #include<iostream>
> 
> using namespace std;
> #define Max 10002
> int ta,tb,a[Max],b[Max],c[Max],sa[Max],sb[Max],sc[Max];
> int d[1002];
> int n,maxa,maxb;
> void bellman()
> {
> 	int k=0,i;
>    bool used=false;
>    memset(d,0,sizeof(d));
>    d[n]=-1;
>    while(!used)
>    {
> 	   k++;
> 	   if(k>=n)
> 		   break;
> 	   used=true;
> 	   for(i=0;i<ta;i++)
> 	   {
> 		   if(d[b[i]]<d[a[i]])
> 			   d[b[i]]=d[a[i]],used=false;
> 		   if(d[b[i]]<d[a[i]]+c[i])
> 		   {
> 			   d[b[i]]=d[a[i]]+c[i];
> 			   used=false;
> 		   }
> 		 
> 	   }
> 
> 		   for(i=0;i<tb;i++)
> 		   {
> 			   if(d[sb[i]]<d[sa[i]])
> 				   d[sa[i]]=d[sb[i]],used=false;
> 			   if(d[sb[i]]>d[sa[i]]+sc[i])
> 			   {
> 				   d[sa[i]]=d[sb[i]]-sc[i];
> 				   used=false;
> 			   }
> 			   
> 		   }
> 
> 			 for(i=2;i<=n;i++)
> 				   if(d[i]<d[i-1])
> 				   {
> 					   used=false;
> 					   d[i]=d[i-1];
> 				   }
> 
> 
>    }
>    if(d[n]<0)
> 	   cout<<-2<<endl;
>    else if(k>=n)
> 	   cout<<-1<<endl;
>    else
> 	   cout<<d[n]-d[1]<<endl;
>    
> 
> }
> int main()
> {
> 	int i;
> 	scanf("%d%d%d",&n,&ta,&tb);
> 	for(i=0;i<ta;i++)
> 	{
> 		scanf("%d%d%d",&a[i],&b[i],&c[i]);
> 		if(a[i]>b[i])
> 			swap(a[i],b[i]);
> 		//maxa=b[i]>maxa?b[i]:maxa;
> 	}
> 	for(i=0;i<tb;i++)
> 	{
> 		scanf("%d%d%d",&sa[i],&sb[i],&sc[i]);
> 		if(sa[i]>sb[i])
> 			swap(sa[i],sb[i]);
> 		//	maxb=b[i]>maxb?b[i]:maxb;
> 	}
>    bellman();
> 	return 0;
> }
>