#include<bits/stdc++.h>
using namespace std;
int n,m,k,f[2501][2501],vis[2501];
long long v[2501],ans=LLONG_MIN;
int main(){
	scanf("%d%d%d",&n,&m,&k);
	for(int i=2;i<=n;i++){
		scanf("%d",&v[i]);
	}
	for(int i=1;i<=m;i++){
		int u,v;
		scanf("%d%d",&u,&v);
		f[u][v]=1;
		f[v][u]=1;
	}
	for(int K=1;K<=n;K++){
		for(int i=1;i<=n;i++){
			for(int j=1;j<=n;j++){
				f[i][j]=min(f[i][j],f[i][K]+f[K][j]);
			}
		}
	}
	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++){
			f[i][j]-=1;
		}
		cout<<endl;
	}
	for(int i=2;i<=n;i++){
		if(f[1][i]>k) continue;
		for(int j=i+1;j<=n;j++){
			if(f[i][j]>k) continue;
			for(int K=j+1;K<=n;K++){
				if(f[j][K]>k) continue;
				for(int l=K+1;l<=n;l++){
					//cout<<i<<" "<<j<<" "<<K<<" "<<l<<endl;
					if(f[K][l]>k||f[l][1]>k) continue;
					ans=max(ans,v[i]+v[j]+v[K]+v[l]);
					//cout<<i<<" "<<j<<" "<<K<<" "<<l<<endl;
				} 
			}
		}
	}
	printf("%lld",ans);
	return 0;
}
/*
7 9 0
1 1 1 2 3 4
1 2
2 3
3 4
1 5
1 6
1 7
5 4
6 4 
7 4
*/

RT，本人心态已经崩掉了……