#include<bits/stdc++.h>
using namespace std;

vector<int> v[100010];
int a[100010], num[100010];

int main()
{
	int n, m;
	cin >> n >> m;
	for(int i = 1; i <= n; i ++) {
		cin >> a[i];
	}
	for(int i = 1; i <= m; i ++) {
		int x, y;
		cin >> x >> y;
		v[x].emplace_back(y);
		v[y].emplace_back(x);
		num[x] ++;
		num[y] ++;
	}
	int ans = 0;
	for(int i = 1; i <= n; i ++) {
		if(num[i] % 2 == 0) {
			ans = max(ans, a[i]);
		} else {
			int j = v[i][0];
			int mx1 = 0, mx2 = 0;
			for(auto x : v[j]) {
				if(num[x] % 2 == 1) {
					if(a[x] >= mx1) {
						mx2 = mx1;
						mx1 = a[x];
						
					} else if(a[x] >= mx2) {
						mx2 = a[x];
					}
				}
			}
			ans = max(ans, min(mx1, mx2));
		}
	}
	cout << ans;
}