//```// YF YUSUF
#define Free_open(File) freopen((File".in"),"r",stdin);freopen((File".out"),"w",stdout);
#define YF ios_base::sync_with_stdio(0);cout.setf(ios::fixed);
#define YUSUF cout.precision(0);cout.tie(0);cin.tie(0);
#include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <unordered_map>
#include <cmath>
#include <numeric>
#include <queue>
#include <stack>
#include <cassert>
#include <climits>
#include <string>
using namespace std;
#ifdef YF_CHECK
bool Output=1;
// #include "g/debug.h"
// #include "g/bigint.h"
// #include "g/text.h"
#else
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize ("inline")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("O3")
bool Output=0;
#define deb(x...) 42
#endif
#ifdef DEV
bool LOUT=1;
#else
bool LOUT=0;
#endif
using ll = long long;
using ld = long double;
using sll = set <ll>;
using vll = vector <ll>;
using mll = map <ll,ll>;
using pll = pair <ll,ll>;
using vvl = vector <vll>;
using vpll = vector <pll>;
template<class T>T MIN(T&a,T b){a=min(a,b);return a;}
template<class T>T MAX(T&a,T b){a=max(a,b);return a;}
#define revers(a) reverse(all(a))
#define all(a) a.begin(),a.end()
#define sortt(a) sort(all(a))
#define sgr v+v+1,(tl+tr)/2+1,tr
#define sgl v+v,tl,(tl+tr)/2
#define pb push_back
#define ins insert
#define S second
#define F first
ll BP(ll a,ll b,ll mod=1e9+7){
if(b==0)return 1;
ll q=BP(a,b/2,mod);
return ((q*q)%mod*(b%2?a:1ll))%mod;
}
ll f(ll x){return x*(x+1)/2;}
ll dup(ll a,ll b){return (a+b-1)/b;}
ll lcm(ll a,ll b){return a/__gcd(a,b)*b;}
ll invf(ll x){return (-1+sqrt(1+8*x))/2;}
const ll mod=998244353;
const ll INF=1e18;
const ll inf=1e9+7;
const ll N =1e6+7;
vll a(N);
vpll K,g[N];
ll ans,n,m,k;
struct DSU{
vll p,sz;
vvl g;
vll b;
void build(ll n){
p.resize(n+1, 0);
sz.resize(n+1, 1);
g.resize(n+1,(vll){});
b.resize(n+1, 0);
for(int i=1;i<=n;i++){
p[i] = i;
sz[i] = 1;
}
}
ll get(ll x){
if(p[x]==x)return x;
else return p[x] = get(p[x]);
}
bool check(ll a,ll b){
a = get(a);
b = get(b);
return (a!=b);
}
bool up(ll a,ll b){
ll A = a, B = b;
a = get(a);
b = get(b);
if(a==b)return 0;
if(sz[a] < sz[b])swap(a,b);
p[b] = a;
sz[a] += sz[b];
sz[b] = 0;
g[A].pb(B);
g[B].pb(A);
return 1;
}
void dfs(ll v,ll p){
b[v] = a[v];
for(auto to : g[v])if(to!=p){
dfs(to, v);
b[v] += b[to];
}
}
void rollback(){
return;
}
};
void YF_MAIN(ll TEST){
cin>>n>>m>>k;
vvl E;
map<ll, vpll> mp;
vll cs;
for(int i=1;i<=m;i++){
ll v,u,w;
cin>>v>>u>>w;
mp[w].pb({v, u});
cs.pb(w);
g[v].pb({w,u});
g[u].pb({w,v});
E.pb({w,v,u});
}
sortt(E);
sortt(cs);
for(int i=1;i<=k;i++){
ll v,u;
cin>>v>>u;
K.pb({v,u});
}
ll A = K[0].F, B = K[0].S;
for(int i=1;i<=n;i++){
cin>>a[i];
}
ll cost = 0;
for(auto C : cs){
mp[C].pb({A,B});
bool used = 0;
DSU dsu; dsu.build(n);
for(auto [w, V] : mp) {
for(int j=V.size()-1;j>=0;j--){
auto [v, u] = V[j];
bool b = dsu.up(v, u);
if((v==A && u==B && b)||(v==B && u==A && b))used=1;
}
}
if(!used)break;
dsu.dfs(1,1);
MAX(cost, C * min(dsu.b[A], dsu.b[B]));
mp[C].pop_back();
}
cout<<cost;
}
bool TECT=0;
bool CASE=0;
bool OUTP=1;
const ll LN=1e1 + 7; ll lg[LN];
const ll SN=2e1 + 7; ll SM[SN];
const ll FN=2e6 + 7;
ll FACT[FN],inv[FN],FMOD=inf;
ll PER(ll n,ll k){return FACT[n] *inv[n-k]%FMOD;}
ll CNK(ll n,ll k){return PER(n,k)*inv[k ]%FMOD;}
void BEFORE(){
for(ll i=2;i<SN;i++){
if(SM[i])continue;
for(ll j=i;j<SN;j+=i)
MAX(SM[j],i);
}
for(int i=2;i<LN;i++) lg[i]=lg[i/2]+1;
FACT[0]=inv[0]=1;
for(int i=1;i<FN;i++){
FACT[i]=FACT[i-1]*i%FMOD;
if(i<5e5+7)inv[i]=BP(FACT[i],FMOD-2,FMOD);
}
}
signed main(){
if(OUTP){YF YUSUF}
// freopen(("input.txt"),"r",stdin);freopen(("output.txt"),"w",stdout);
// Free_open("TEST");
cout<<(LOUT && Output ? "\nYF_OUTPUT:\n\n" : "");
int TEST=1;
if(TECT)
cin>>TEST;
BEFORE();
for(int T=1;T<=TEST;T++){
if(CASE)
cout<<"Case "<<T<<": ";
YF_MAIN(T);
cout<<(T==TEST ? "" : "\n");
}
return 0;
}
//```
