#include<bits/stdc++.h>
using namespace std;
vector<int>p[100009];
int ans1=1e9,ans2=-1,v[100009],a[100009];
void dfs(int x){
	if (p[x].size()==1){
		ans1=min(ans1,a[x]);
		if (x!=1)
		return ;
	}
	else{
		ans2=max(ans2,a[x]);
	}
	for (auto i : p[x]){
		if (v[i]){
			continue;
		}
		v[i]=1;
		dfs(i);
	}
}
int main(){
	int n,x,y,m,i;
	cin>>n>>m;
	for (i=0;i<n;i++){
		cin>>a[i+1];
	}
	for (i=0;i<m;i++){
		cin>>x>>y;
		p[x].push_back(y);
		p[y].push_back(x);
	}
	v[1]=1;
	dfs(1);
	//cout<<ans1<<" "<<ans2<<" ";
	if (ans1==1e9){
		ans1=0;
	}
	if (ans2==-1){
		ans2=0;
	}
	cout<<max(ans1,ans2);
}