#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const ll N = 3e5 + 9;
const ll inf = 0x3f3f3f3f;

ll n,m,a[N];
vector<ll> g[N];

void solve() {
	cin>>n>>m;
	ll minn = inf;
	for(int i=  1;i<=n;i++){
		cin>>a[i];//重量
		minn = min(a[i],minn);
		g[i].clear();
	} 
	for(int i = 1;i<=m;i++){
		ll u,v;cin>>u>>v;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	ll ans = minn;
	for(int i = 1;i<=n;i++){
		if(g[i].size()>=2){
			bool flag = 1;
			for(auto &v:g[i]){
				if(g[v].size() == 2){
					for(auto &y:g[v]){
						if(y == i) continue;
						if(g[y].size() == 1) flag = 0;
					}
				}
			}
			if(flag) ans = max(ans,a[i]);
		}
	}
	cout<<ans<<"\n";
}

signed main() {
	int _ = 1;//cin >> _;
	while (_--) solve();
	return 0;
}