// #pragma GCC optimize(2)
// #pragma GCC optimize(3,"Ofast","inline")
#include <bits/stdc++.h>
using namespace std;
#define x first
#define y second
#define int long long
#define endl '\n'
using i128 = __int128;
using i64 = long long;
using f128 = long double;
using u64 = unsigned long long;
using pii = pair<int, int>;
const int INF = 0x3f3f3f3f, mod = 1e9 + 7;
const i64 inf = 2e18;
//-------------------------------------------
void solve()
{
  int n, m;
  cin >> n >> m;
  vector<pii> w(n + 1);
  for (int i = 1; i <= n; i++)
  {
    cin >> w[i].x;
    w[i].y = i;
  }

  vector<int> d(n + 1);
  for (int i = 1; i <= m; i++)
  {
    int x, y;
    cin >> x >> y;
    d[x]++, d[y]++;
  }
  sort(w.begin() + 1, w.end(), [&](pii x, pii y)
       { return x.x > y.x; });
  for (int i = 1; i <= n; i++)
  {
    if (d[w[i].y] >= 2 || d[w[i].y] == 0)
    {
      cout << w[i].x << endl;
      return;
    }
  }
}
signed main()
{
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int T = 1;
  // cin >> T;
  for (int i = 1; i <= T; i++)
    solve();
  return 0;
}