#include <bits/stdc++.h>
using namespace std;
inline long long mod(long long n, long long m) {
  long long ret = n % m;
  if (ret < 0) ret += m;
  return ret;
}
long long gcd(long long a, long long b) { return (b == 0 ? a : gcd(b, a % b)); }
long long exp(long long a, long long b, long long m) {
  if (b == 0) return 1;
  if (b == 1) return mod(a, m);
  long long k = mod(exp(a, b / 2, m), m);
  if (b & 1) {
    return mod(a * mod(k * k, m), m);
  } else
    return mod(k * k, m);
}
map<vector<long long>, long long> mp;
long long a[500100];
vector<long long> adj[500100];
void solve() {
  mp.clear();
  long long n, m;
  cin >> n >> m;
  for (long long i = 1; i <= n; i++) {
    adj[i].clear();
    cin >> a[i];
  }
  for (long long i = 0; i < m; i++) {
    long long a, b;
    cin >> a >> b;
    adj[b].push_back(a);
  }
  for (long long i = 1; i <= n; i++) {
    sort(adj[i].begin(), adj[i].end());
    if (adj[i].size()) {
      mp[adj[i]] += a[i];
    }
  }
  long long g = -1;
  for (map<vector<long long>, long long>::iterator it = mp.begin();
       it != mp.end(); it++) {
    if (g == -1)
      g = it->second;
    else
      g = gcd(g, it->second);
  }
  if (g == -1) g = 0;
  cout << g << "\n";
}
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long t;
  cin >> t;
  while (t--) {
    solve();
  }
}
