#include <bits/stdc++.h>
#define max(a,b) (a>b?a:b)
#define min(a,b) (a<b?a:b)
// #define int unsigned long long
#define endl '\n'
using namespace std;
typedef long long LL;
typedef pair<LL,int > PII;
const int N = 2505;
const int M = 1e4+5;

LL w[N];
int pre[N];
struct node{
    int to,next;
}e[M*2];

int n,m,tot,k;
int dis[N][N];
bool f[N];

int q[N],h,t;
set<PII > st[N];

inline void add(int u,int v){
    e[++tot] = {v,pre[u]};
    pre[u] = tot;
}

inline void bfs(int x){
    memset(f,0,sizeof(f));
    f[x] = h = t = 1;
    q[1] = x,dis[x][x] = 0;
    
    while(h <= t){
        int p = q[h];
        for(int i = pre[p]; i; i = e[i].next){
            if(!f[e[i].to]){
                dis[x][e[i].to] = dis[x][p] + 1;
                if(dis[x][e[i].to] <= k)
                    q[++t] = e[i].to;
                f[e[i].to] = true;
            }
        }
        h++;
    }
}

signed main(){
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    int x,y;
    
    cin >> n >> m >> k;
    for(int i = 2; i <= n; i++)
        cin >> w[i];
    for(int i = 1; i <= m; i++){
        cin >> x >> y;
        add(x,y),add(y,x);
    }
    
    memset(dis,0x3f,sizeof(dis));
    for(int i = 1; i <= n; i++){
        bfs(i);
    }
    
    for(int i = 2; i <= n; i++){
        for(int j = 2; j <= n; j++){
            if(i != j && dis[i][j] < k && dis[1][j] < k){
                st[i].insert({w[j],j});
                if(st[i].size() > 3)
                    st[i].erase(st[i].begin());
            }
        }
    }
    
    LL ans = 0;
    for(int b = 2; b <= n; b++){
        for(int c = 2; c <= n; c++){
            if(b != c && dis[b][c] < k){
                for(auto a : st[b]){
                    if(a.second == c)
                        continue;
                    for(auto d : st[c]){
                        if(d.second == a.second || d.second == b)
                            continue;
                        ans = max(ans,w[b]+w[c]+w[a.second]+w[d.second]);
                    }
                }
            }
        }
    }
    
    cout << ans << endl;
    return 0;
}