Untitled

#include<iostream>
using namespace std;
int TC, N, M, H, a[1005][1005], am[1005], v[1005], maxr, maxi;
void dfs(int k, int c) {
	v[k] = c;
	for(int i = 1; i <= a[k][0]; i++) {
		if(v[a[k][i]] == -1) {
			dfs(a[k][i], c + 1);
		} else {
			if(v[a[k][i]] > c + 1) {
				dfs(a[k][i], c + 1);
			}
		}
	}
}

int main() {
	/*freopen("input.txt", "r", stdin);*/
	cin >> TC;
	for(int tc = 1; tc <= TC; tc++) {
		cin >> N >> M >> H;
		for(int i = 0; i < M; i++) cin >> am[i];
		for(int i = 0; i < N; i++) a[i][0] = 0;
		fill_n(v, N, -1);
		for(int i = 0; i < H; i++) {
			int x, y;
			cin >> x >> y;
			a[x][0]++, a[y][0]++;
			a[x][a[x][0]] = y, a[y][a[y][0]] = x;
		}
		for(int i = 0; i < M; i++) {
			dfs(am[i], 0);
		}
		maxr = -1, maxi = -1;
		for(int i = 0; i < N; i++) {
			if((v[i] != -1 && v[i] > maxr) || v[i] == -1) {
				if(v[i] == -1) {
					maxi = i;
					break;
				}
				maxr = v[i], maxi = i;
			}
		}
		cout << maxi << endl;
	}
	return 0;
}