#include<bits/stdc++.h>
#define int long long
#define endl '\n'
#define vi vector<int>
#define vll vector<long long>
#define double long double
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<'*'<<x<<'\n';
#define yes cout<<"YES\n";
#define no cout<<"NO\n";
#define rep(x, y) for(int i=(x); i<=(y); i++)
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
const int INF=0x3f3f3f3f;
const ll LINF=0x3f3f3f3f3f3f3f3f;
const int mod=1e9+7;
ll gcd(ll a,ll b)
{
	return b?gcd(b,a%b):a;
}
ll lcm(ll a,ll b)
{
	return a*b/gcd(a,b);
}
ll qmi(ll a,ll b)
{
	ll ans=1;
	while(b)
	{
		if(b&1)ans=ans*a%mod;
		a=a*a%mod;
		b>>=1;
	}
	return ans;
}




void solve()
{
	int n, m;
	cin >> n >> m;
	vi a(n+1);
	int res = LINF;
	priority_queue<pii>q;
	rep(1, n)cin >> a[i], q.push({a[i], i}), res = min(res, a[i]);
	vi d(n+1, 0);
	rep(1, m)
	{
		int x, y;
		cin >> x >> y;
		d[x] ++;
		d[y] ++;
	}
	int u = LINF;
	rep(1, n)
	{
		if(d[i] == 1)u = min(u, a[i]);
	}
	while(q.size())
	{
		pii t = q.top();
		q.pop();
//		debug(d[t.second]);
		if(d[t.second] > 1)
		{
			if(u == LINF)u = 0;
			cout << max(u, t.first) << endl;
			return;
		}
	}
	cout << res << endl;
}



signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0),cout.tie(0);
	int _;
	_=1;
//	cin>>_;
	while(_--)solve();
	return 0;
}