Untitled

package he_thong_dien;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Solution {
	static int n, m, h, res, max;
	static int[][] a;
	static int[] b, vt;

	static void dfs(int dinh, int c) {
		
		b[dinh] = c;
		for (int i = 0; i < a[dinh][n]; i++) {
			if(b[a[dinh][i]] == -1){
				dfs(a[dinh][i], c+ 1);
			}else if(b[a[dinh][i]] > c + 1){
				dfs(a[dinh][i], c+ 1);
			}
		}

	}

	public static void main(String[] args) {

		try {
			System.setIn(new FileInputStream("input.txt"));
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}

		Scanner scanner = new Scanner(System.in);
		int test = scanner.nextInt();
		for (int t = 0; t < test; t++) {
			n = scanner.nextInt();
			m = scanner.nextInt();
			h = scanner.nextInt();
			a = new int[n][n + 1];
			b = new int[n];
			vt = new int[m];
			for (int i = 0; i < n; i++) {
				b[i] = -1;
			}

			for (int i = 0; i < m; i++) {
				int x = scanner.nextInt();
				b[x] = 0;
				vt[i] = x;
			}

			for (int i = 0; i < h; i++) {
				int x = scanner.nextInt(), y = scanner.nextInt();
				a[x][a[x][n]] = y;
				a[x][n]++;
				a[y][a[y][n]] = x;
				a[y][n]++;
			}

			

			res = 0;
			max = 0;

			for (int i = 0; i < m; i++) {
				
					dfs(vt[i], 0);

			}

			for (int i = 0; i < n; i++) {
				if (b[i] > max) {
					max = b[i];
					res = i;
				}
				if(b[i] == -1){
					res = i;
					break;
				}
			}

			System.out.println(res);
		}
		scanner.close();
	}
}