#include<bits/stdc++.h>
#define endl '\n'
#define ll long long
#define pii pair<ll, ll>
const ll inf = 2e18;
const double eps = 1e-9;
using namespace std;
#define int long long
void slv(){
    ll n, m; cin >> n >> m;
    vector<pii> a(n + 1); for(int i = 1; i <= n; ++i) {
        cin >> a[i].first;
        a[i].second = i;
    }
    if(n == 1) {
        cout << a[1].first << endl;
        return ;
    }


    vector<int> in(n + 1);
    for(int cnm = 1, x, y; cnm <= m; ++cnm) {
        cin >> x >> y;
        in[x]++, in[y]++;
    }

    sort(a.begin(), a.end(), [&](pii x, pii y) {
        return x.first > y.first;
    });


    if(in[a[1].second] >= 2) {
        cout << a[1].first << endl;
    } else {
        cout << a[2].first << endl;
    }
}

main(){
    //ios::sync_with_stdio(0), cin.tie(0);
    int _ = 1;
    //cin >> _;
    while(_--) slv();
    return 0;
}
/*
7 7
1 1 2 3 1 2 1
1 2
2 3
1 3
2 4
2 5
5 6
5 7
 */