#include <bits/stdc++.h>   using namespace std;   vector<int> h;   vector<vector<int> > g;   int h0, v0;   vector<int> val;   int it = 0;   vector<bool> used;   vector<int> treesum, par;   vector<int> treemin;   void update(int v, int l, int r, int ind, int d) {     if (l == r) {       treesum[v] += d;       treemin[v] += d;       return;     }     if (ind <= (r + l) / 2) {       update(v * 2, l, (r + l) / 2, ind, d);     } else {       update(v * 2 + 1, (r + l) / 2 + 1, r, ind, d);     }     treesum[v] = treesum[v * 2] + treesum[v * 2 + 1];     treemin[v] = min(treemin[v * 2], treesum[v * 2] + treemin[v * 2 + 1]);   }   int query(int v, int l, int r, int x) {     if (l == r) {       return l;     }     if (treemin[v * 2] + x < 0) {       return query(v * 2, l, (r + l) / 2, x);     }     return query(v * 2 + 1, (r + l) / 2 + 1, r, treesum[v * 2] + x);   }   void dfs1(int v, int p = -1) {     for (int i = 0; i < g[v].size(); i++) {       int to = g[v][i];       if (to != p) {         val[to] = min(val[v], h[v]);         par[to] = v;         dfs1(to, v);       }     }   }   vector<int> uniq;   int m;   int mass[1000000];   void dfs2(int v) {     mass[++it] = v;     for (int i = 0; i < g[v].size(); i++) {       int to = g[v][i];       if (to != par[v]) {         if (val[to] < h[to]) {           dfs2(to);         }       }     }   }   signed main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int n, k;     cin >> n;     used.resize(n);     g.resize(n);     h.resize(n);     par.resize(n, -1);     val.resize(n);     for (int i = 0; i < n; i++) {       cin >> h[i];       uniq.push_back(h[i]);     }     for (int i = 0; i < n - 1; i++) {       int a, b;       cin >> a >> b;       a--;       b--;       g[a].push_back(b);       g[b].push_back(a);     }     cin >> k;     vector<int> s(k);     for (int i = 0; i < k; i++) {       cin >> s[i];       uniq.push_back(s[i]);     }     sort(uniq.begin(), uniq.end());     m = unique(uniq.begin(), uniq.end()) - uniq.begin();     treesum.resize(4 * m, 0);     treemin.resize(4 * m, 0);     for (int i = 0; i < n; i++) {       h[i] = lower_bound(uniq.begin(), uniq.begin() + m, h[i]) - uniq.begin();     }     for (int i = 0; i < k; i++) {       s[i] = lower_bound(uniq.begin(), uniq.begin() + m, s[i]) - uniq.begin();     }     val[0] = 1e9;     dfs1(0);     for (int i = 0; i < n; i++) {       update(1, 0, m - 1, m - min(val[i], h[i]) - 1, 1);     }     for (int i = 0; i < k; i++) {       update(1, 0, m - 1, m - s[i] - 1, -1);     }     if (treemin[1] >= 0) {       cout << 0;       return 0;     }     int ans = 1e9;     vector<int> b(n);     for (int i = 0; i < n; i++) {       if (h[i] < val[i]) {         it = 0;         dfs2(i);         update(1, 0, m - 1, m - h[i] - 1, -it);         int t = m - query(1, 0, m - 1, 0) - 1;         if (t <= val[i]) {           b[i] = t;           update(1, 0, m - 1, m - t - 1, 1);           for (int j = 2; j <= it; j++) {             b[mass[j]] = min(h[mass[j]], b[par[mass[j]]]);             update(1, 0, m - 1, m - b[mass[j]] - 1, 1);           }           if (treemin[1] >= 0) {             ans = min(ans, uniq[t] - uniq[h[i]]);           }           for (int j = 1; j <= it; j++) {             update(1, 0, m - 1, m - b[mass[j]] - 1, -1);           }         }         update(1, 0, m - 1, m - h[i] - 1, it);       }     }     if (ans == 1e9) {       cout << -1;     } else {       cout << ans;     }     return 0;   }