#include <bits/stdc++.h>
using namespace std;
using i64 = long long;

void solve() {
    int n, m;
    cin >> n >> m;
    vector<int> a(n + 1);
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    vector<vector<int>> adj(n + 1);
    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        adj[a].emplace_back(b);
        adj[b].emplace_back(a);
    }

    auto check = [&](int w) {
        for (int i = 1; i <= n; i++) {
            if (a[i] < w) continue;
            if (adj[i].size() >= 2) {
                return true;
            }
        }
        return false;
    };

    int l = 1, r = n;
    while (l < r) {
        int mid = l + r + 1 >> 1;
        if (check(mid)) {
            l = mid;
        } else {
            r = mid - 1;
        }
    }
    cout << l << "\n";
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int t = 1;
    // cin >> t;

    while (t--) {
        solve();
    }

    return 0;
}