#include <bits/stdc++.h>

#define DEBUG
#ifdef DEBUG
#define debug(x) cerr << #x << ": " << (x) << endl
#define print(x) cerr << x << ' '
#define println(x) cerr << x << endl
#else
#define debug(x)
#define print(x)
#define println(x)
#endif
#define x first
#define y second
#define el '\n'
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int N = 3e5 + 10, INF = 0x3f3f3f3f, mod = 998244353;

void solve() {
    int n, m; cin >> n >> m;
    vector<int> deg(n), a(n), p(n);
    for (int i = 0; i < n; ++i) cin >> a[i];
    while (m--) {
        int a, b; cin >> a >> b;
        --a, --b;
        ++deg[a], ++deg[b];
    }
    iota(p.begin(), p.end(), 0);
    sort(p.begin(), p.end(), [&](int i, int j) {
        return a[i] > a[j];
    });
    for (int i: p) {
        if (deg[i] != 1) return cout << a[i] << el, void();
    }
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    int tcase = 1;
    // cin >> tcase;
    while (tcase--) solve();
}