#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<vector>
#include<cstdio>
#include<queue>
#include<algorithm>
#include<cstring>
using namespace std;

const int INF = 987654321;
const int MAX_V=115;

int V, N, M;
int capacity[MAX_V][MAX_V], flow[MAX_V][MAX_V];

vector<int> wins;
vector<pair<int, int> > match;

int networkFlow(int source, int sink) {
    memset(flow, 0, sizeof(flow));
    int totalFlow = 0;
    while (1) {
        vector<int> parent(MAX_V, -1);
        queue<int> q;
        parent[source] = source;
        q.push(source);
        while (!q.empty() && parent[sink] == -1) {
            int here = q.front(); q.pop();
            for (int there = 0; there < V; ++there)
            if (capacity[here][there] - flow[here][there] > 0 && parent[there] == -1) {
                q.push(there);
                parent[there] = here;
            }
        }
        if (parent[sink] == -1) break;
        int amount = INF;
        for (int p = sink; p != source; p = parent[p])
            amount = min(capacity[parent[p]][p] - flow[parent[p]][p], amount);
        for (int p = sink; p != source; p = parent[p]) {
            flow[parent[p]][p] += amount;
            flow[p][parent[p]] -= amount;
        }
        totalFlow += amount;
    }

    return totalFlow;
}

bool solve(int total){
    for (int i = 1; i < N; ++i){
        if (wins[i] >= total)
            return false;
    }
    V = N + M + 2;
    memset(capacity, 0, sizeof(capacity));
    for (int i = 0; i < M; ++i){
        capacity[0][2 + i] = 1;
        capacity[2 + i][2 + M + match[i].first] = 1;
        capacity[2 + i][2 + M + match[i].second] = 1;
    }

    for (int i = 0; i < N; ++i){
        int max_wins = (i == 0 ? total : total - 1);
        capacity[2 + M + i][1] = max_wins - wins[i];
    }
    return networkFlow(0, 1) == M;
}

int main() {
    int c;
    cin >> c;
    while (c--){
        cin >> N >> M;
        wins = vector<int>(N);
        match = vector<pair<int,int> >(M);

        for (int i = 0; i < N; ++i)
            cin >> wins[i];

        int ret = 0;
        for (int i = 0; i < M; ++i){
            cin >> match[i].first >> match[i].second;
            if (match[i].first == 0 || match[i].second == 0)
                ++ret;
        }

        bool success = false;
        for (int i = 0; i <= 1500; ++i){
            if (wins[0] + ret < i)
                break;
            if (solve(i)){
                cout << i << endl;
                success = true;
                break;
            }
        }

        if (!success)
            cout << -1 << endl;
    }
    return 0;
}