#include<bits/stdc++.h>
using namespace std;
const int N=100010;
int w[N];
vector<int>G[N];
int main()
{
    int n,m;
    scanf("%d %d",&n,&m);
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&w[i]);
    }
    for(int i=1;i<=m;i++)
    {
        int x,y;
        scanf("%d %d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    int ans_1=0;
    int ans_2=114514;
    for(int i=1;i<=n;i++)
    {
        if(G[i].size()>1)ans_1=max(w[i],ans_1);
        else if(G[i].size()==1)ans_2=min(ans_2,w[i]);
    }
    if(n==1)printf("%d\n",w[1]);
    else printf("%d\n",max(ans_1,ans_2));
    return 0;
}