思路抽象，望有大佬求调QAQ WA #1, 5, 21, 31 TLE #18, 19, 20, 25, 26, 44, 45, 46

#include<bits/stdc++.h>
#define int long long
using namespace std;
struct edge{
	int l, r, useable;
};
struct node{
	int ax[3] = {-1, -1, -1};
	int id[3] = {-1, -1, -1};
	int get_num(int a){
		return ax[a];
	};
	int get_id(int a){
		return id[a];
	};
	void insert(int a, int b){
		for(int i = 0; i < 3; i++){
			if(b == id[i]){
				return;
			}
			if(a > ax[i]){
				for(int j = 2; j >= j + 1; j--){
					ax[j] = ax[j - 1];
					id[j] = id[j - 1];
				}
				id[i] = b;
				ax[i] = a;
				return;
			}
		}
	};
};
vector<edge> alle;
vector<int> nodes[3000];
node abc[3000];
int val[3000], ans = 0;
int n, m, k, l, r, ecn, vis[3000], depth[3000], reach1[3000], fir[3000][3000];
void add_edge(int ll, int rr, int usea){
	alle.push_back((edge){ll, rr, usea});
	nodes[ll].push_back(ecn);
	ecn++;
	alle.push_back((edge){rr, ll, usea});
	nodes[rr].push_back(ecn);
	ecn++;
}
void bfs(int st){
	queue<int> q;
	q.push(st);
	vis[st] = st;
	depth[st] = 0;
	while(q.size()){
		int now_node = q.front();
		q.pop();
		for(int i = 0; i < nodes[now_node].size(); i++){
			edge e = alle[nodes[now_node][i]];
			if(vis[e.r] != st && e.useable){
				depth[e.r] = depth[now_node] + 1;
				q.push(e.r);
				vis[e.r] = st;
				if(st == 1 && depth[e.r] <= k + 1){
					reach1[e.r] = 1;
				}
				if(depth[e.r] <= k + 1 && !fir[st][e.r]){
					add_edge(st, e.r, 0);
					fir[st][e.r] = fir[e.r][st] = 1;
				}
			}
		}
	}
}
void cal(int x){
	for(int i = 0; i < nodes[x].size(); i++){
		edge e = alle[nodes[x][i]];
		if(reach1[e.r]){
			abc[x].insert(val[e.r], e.r);
		}
	}
}
signed main(){
    clock_t st = clock();
	cin >> n >> m >> k;
	for(int i = 2; i <= n; i++){
		cin >> val[i];
	}
	for(int i = 1; i <= m; i++){
		cin >> l >> r;
		add_edge(l, r, 1);
		fir[l][r] = 1;
		fir[r][l] = 1;
	}
	for(int i = 1; i <= n; i++){
		bfs(i);
	}
	for(int i = 2; i <= n; i++){
		cal(i);
	}
	for(int i = 2; i <= n; i++){
		for(int j = 2; j <= n; j++){
		    if((double)(clock() - st) / CLOCKS_PER_SEC >= 2.1){
		        break;
		    }
			if(!fir[i][j]){
				continue;
			}
			if(i != j){
				for(int kk = 0; kk < 3; kk++){
					int id1 = abc[i].get_id(kk);
					if(id1 == -1 || id1 == j){
						continue;
					}
					for(int ll = 0; ll < 3; ll++){
						int id2 = abc[j].get_id(ll);
						if(id2 == -1 || id2 == id1 || id2 == i){
							continue;
						}
						ans = max(ans, val[i] + val[j] + abc[j].get_num(ll) + abc[i].get_num(kk));
					}
				}
			}
		}
	}
	cout << ans;
}