#include<bits/stdc++.h>
#define LL long long
using namespace std;
vector<int> e[2505];
int vis[2505][2505],dis[2505][2505],tmp[2505];
LL s[2505];
queue<int>q;
int n,m,k;
bool cmp(int i,int j){return s[i]>s[j];}
main()
{
	scanf("%d%d%d",&n,&m,&k);
	for (int i=1;i<n;++i)
		scanf("%lld",&s[i+1]);
	++k;
	for (int u,v,i=1;i<=m;++i)
	{
		scanf("%d%d",&u,&v);
		e[u].push_back(v);
		e[v].push_back(u);
	}
	memset(dis,63,sizeof(dis));
	for (int x,i=1;i<=n;++i)
	{
		dis[i][i]=0;
		for (q.push(i);!q.empty();q.pop())
		{
			x=q.front();
			if (dis[i][x]==k) continue;
			for (int j=0;j<e[x].size();++j)
				if (dis[i][e[x][j]]>k)
					dis[i][e[x][j]]=dis[i][x]+1,
//					vis[i][++vis[i][0]]=e[x][j],
					q.push(e[x][j]);
		}
//		sort(vis[i]+1,vis[i]+vis[i][0]+1,cmp);
	}
	for (int j=2;j<=n;++j)
	{
		for (int i=2;i<=n;++i)
			if (i!=j&&dis[1][i]<=k&&dis[i][j]<=k)
				vis[j][++vis[j][0]]=i;
		sort(vis[j]+1,vis[j]+vis[j][0]+1,cmp);
	}
	LL ans=0;
	for (int i=2;i<=n;++i)
		for (int j=i+1;j<=n;++j)
		if (dis[i][j]<=k)
			for (int k=1;k<=min(2,vis[i][0]);++k)
				for (int l=1;l<=min(2,vis[j][0]);++l)
					if (vis[i][k]!=j&&vis[j][l]!=i&&vis[i][k]!=vis[j][l])
						ans=max(ans,s[i]+s[j]+s[vis[i][k]]+s[vis[j][l]]);
	printf("%lld\n",ans);
						
}