#include<bits/stdc++.h>
using namespace std;
bool mp[2501][2501];
int a[2501];
int main()
{
	int n,m,q;
	cin >> n >> m >> q;
	for (int i=2;i<=n;++i)
	{
		cin >> a[i];
	}
	for(int i=1;i<=m;++i)
	{
		int u,v;
		cin >> u >> v;
		mp[u][v]=1;
		mp[v][u]=1;
	}
	int ans=-1;
	for (int i=2;i<=n;++i)
	{
		if (mp[1][i]==0) continue;
		for (int j=2;j<=n;++j)
		{
			if (i==j||mp[i][j]==0) continue;
			for (int k=2;k<=n;++k)
			{
				if (k==j||mp[k][j]==0) continue;
				for (int l=2;l<=n;++l)
				{
					if (k==l||mp[k][l]==0||mp[l][1]==0) continue;
					ans=max(ans,a[i]+a[j]+a[k]+a[l]);
//					cout << i << " " << j << " " << k<< " " << l << " " << a[i]+a[j]+a[k]+a[l] << " " << ans << endl;
				}
			}
		}
	}
	cout << ans << endl;
	return 0;
}