#include <bits/stdc++.h>
using namespace std;
#define int long long
struct DSU{
vector<int> parent,sz;
DSU(int n){
sz.resize(n,1);
parent.resize(n);
for (int i = 0; i<n; i++){
parent[i] = i;
}
}
int find(int x){
if (x == parent[x]){
return x;
}
return parent[x] = find(parent[x]);
}
bool merge(int a, int b){
a = find(a);
b = find(b);
if (a == b) return false;
if (sz[a] < sz[b]) swap(a,b);
parent[b] = a;
sz[a] += sz[b];
return true;
}
bool sam(int a, int b){
//check if two nodes are in the same component
int x = find(a);
int xx = find(b);
return (x == xx);
}
};
const int MAXN = 1e5+5;
vector<pair<int,int>> adj[MAXN];
int sz[MAXN];
int tot = 0;
int arr[MAXN];
int par[MAXN];
int depth[MAXN];
void dfs_sz(int x, int p){
sz[x] = arr[x];
par[x] = p;
for (auto v : adj[x]){
auto [u,w] = v;
if (u == p) continue;
dfs_sz(u,x);
sz[x] += sz[u];
depth[u] = depth[x]+1;
}
}
signed main(){
int n,m,k;
cin >> n >> m >> k;
vector<array<int,3>> edge(m);
for (int i = 0; i<m; i++){
int a,b,w;
cin >> a >> b >> w;
a--;b--;
edge[i] = {w,a,b};
}
sort(edge.begin(), edge.end());
vector<pair<int,int>> mm;
for (int i = 0; i<k; i++){
int a,b;
cin >> a >> b;
a--;b--;
mm.push_back({a,b});
}
for (int i = 0; i<n; i++){
cin >> arr[i];
}
vector<int> ans(k, 0);
for (int z = 0; z<k; z++){
auto [a,b] = mm[z];
//we need to find the cut between a,b
DSU dsu(n);
for (int i = 0; i<edge.size(); i++){
int aa = edge[i][1];
int bb = edge[i][2];
int ww = edge[i][0];
dsu.merge(aa, bb);
if (dsu.sam(a, b)){
ans[z] = ww;
break;
}
}
edge.push_back({ans[z],a,b});
//cout << ans[z] << " " << a << " " << b << '\n';
sort(edge.begin(), edge.end());
}
//now we just construct the MST and then dfs
//simply construct subtree sizes
DSU dsu(n);
for (int i = 0; i<edge.size(); i++){
auto [w,a,b] = edge[i];
if (dsu.merge(a,b)){
adj[b].push_back({a,w});
adj[a].push_back({b,w});
}
}
dfs_sz(0,-1);
for (int i = 0; i<n; i++){
//cout << sz[i] << " ";
}
depth[0] = 0;
for (int i = 0; i<k; i++){
auto [a,b] = mm[i];
if (depth[a] > depth[b]) swap(a,b);
//we ensure A is always parent
tot += ans[i] * sz[b];
}
cout << tot << '\n';
return 0;
}
