#include <bits/stdc++.h>
using namespace std;
using ui = unsigned int;
using ull = unsigned long long;
using ll = long long;
#define endl '\n'
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int maxn = 2e5 + 10;
const int mod = 1000000007;
#define inl inline
#define fr(i, a, b) for (int i = a; i <= b; i++)
#define ford(i, a, b) for (int i = a; i >= b; i--)
#define forall(i, a) for (auto &i : a)

/**
   ____         ___ _____
  / ___| _   _ / _ \___ /
  \___ \| | | | | | ||_ \
   ___) | |_| | |_| |__) |
  |____/ \__, |\___/____/
         |___/
*/
istream &operator>>(istream &in, vector<int> &v)
{
    for (auto &i : v)
        in >> i;
    return in;
}
ostream &operator<<(ostream &out, vector<int> &v)
{
    for (auto &i : v)
        out << i << " ";
    return out;
}
bool _output = 0;

void solve()
{
    int n, m;
    cin >> n >> m;
    vector<int> a(n + 1);
    fr(i, 1, n) cin >> a[i];
    sort(a.begin() + 1, a.end(), greater<int>());
    int mx = *max_element(a.begin() + 1, a.end());
    unordered_map<int, int> mp;
    fr(i, 1, n)
    {
        mp[a[i]]++;
    }
    vector<int> d(n + 1);
    fr(i, 1, m)
    {
        int u, v;
        cin >> u >> v;
        d[u]++;
        d[v]++;
    }
    bool suc = 0;
    fr(i, 1, n)
    {
        if (a[i] == mx && d[i] > 1)
        {
            suc = 1;
        }
    }
    if (suc)
    {
        cout << a[1] << endl;
    }
    else
        cout << a[2] << endl;
}
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int _ = 1;
    if (_output)
        cin >> _;
    while (_--)
        solve();
    return 0;
}