#include<bits/stdc++.h>
#define lowbit(x) (x & (-x))
#define endl "\n"
#define ll long long
#define int long long
// #define ull unsigned long long
#define fi first
#define se second
using namespace std;
#define pii pair<int, int>
#define rep(i, a, b) for(int i = a; i <= b; i ++ )
#define pre(i, a, b) for(int i = a; i >= b; i -- )
#define IOS ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
mt19937_64 rnd(time(0));
const int N = 1e6 + 10;
int n, m;
int in[N], a[N];
void solve()
{
    cin >> n >> m;
    rep(i, 1, n) cin >> a[i];
    rep(i, 1, m)
    {
        int u, v;
        cin >> u >> v;
        in[u] ++ ;
        in[v] ++ ;
    }
    int ans = 0;
    rep(i, 1, n) if(in[i] >= 2) ans = max(ans, a[i]);
    int res = 1e18;
    rep(i, 1, n)
    {
        if(in[i] < 2) res = min(res, a[i]);
    }
    if(res < 10000000) ans = max(ans, res);
    cout << ans;
}
signed main()
{
    IOS;
    int _;
    _ = 1;
    // cin >> _;
    while(_ -- )
    {
        solve();
    }
	return 0;
}