#include <bits/stdc++.h>
using namespace std;
const int N=2510;
int n,m,k;
int a[N],b[N],c[N];
long long head[N],cnt,res=-1;
struct node{
	int next,to,w;
}edge[10010];
void add(int u,int v){
	edge[++cnt].to=v;
	edge[cnt].w=a[v];
	edge[cnt].next=head[u];
	head[u]=cnt;
}
void dfs(int from,long long sum,int cnt){
	if(cnt==4){
		res=max(res,sum);
		return;
	}
	for(int i=head[from];edge[i].next!=0;i=edge[i].next){
		dfs(i,sum+edge[i].w,cnt+1);
	}
}
int main(){
	freopen("csp2022_holiday.in","r",stdin);
	freopen("csp2022_holiday.out","w",stdout);
	cin>>n>>m>>k;
	head[1]=-1;
	for(int i=2;i<=n;i++){
		cin>>a[i];
		head[i]=-1;
	}
	for(int i=1;i<=m;i++){
		int u,v;
		cin>>u>>v;
		add(u,v);
		add(v,u);
	}
	dfs(1,0,0);
	cout<<res;
	return 0;
}