#include<bits/stdc++.h>
using namespace std;
#define int long long    
#define vi vector<int>
#define vii vector<vi>
#define pb push_back
#define pir pair<int,int>
const int P = 1e9 + 7;
const int N = 1e6+7;
const int inf = 0x3f3f3f3f3f3f3f3f;//longlong
const int ing = 1e18;
const int mod = 998244353;
int  n,m;
int ax, bx,ay,by;
int a[20];
int qmi(int a,int b){
	int res=1;
	while(b){
		if(b&1){
			res=res*a%mod;
		}
		a=a*a%mod;
		b>>=1;
	}
	return res;
}
int d[N];
void solve()
{
	cin>>n>>m;
	vector<int> a(n+1);
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	for(int i=1;i<=m;i++){
		cin>>ax>>ay;
		d[ax]++;
		d[ay]++;
	}
	int mx=0;
	for(int i=1;i<=n;i++){
		if(d[i]!=1){
			mx=max(d[i],mx);
		}
	}
	sort(a.begin()+1,a.end());
	if(a[n]==mx){
		cout<<mx<<"\n";
	}
	else {
		cout<<a[n-1]<<"\n";
	}
}
signed main()
{
	cin.tie(0)->sync_with_stdio(0);
	int _ = 1;
	//cin >> _;
	while (_--)
	{
		solve();
	}
}