#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int C = 26;
void add(int &x, int y) {
  x += y;
  while (x >= MOD) x -= MOD;
  while (x < 0) x += MOD;
}
int fix(int x) {
  while (x >= MOD) x -= MOD;
  while (x < 0) x += MOD;
  return x;
}
int pw(int a, int b) {
  int ret = 1;
  while (b) {
    if (b & 1) ret = 1ll * ret * a % MOD;
    b >>= 1;
    a = 1ll * a * a % MOD;
  }
  return ret;
}
const int MAXN = 5e5 + 10;
long long mygcd(long long a, long long b) {
  if (a == 0) return b;
  return mygcd(b % a, a);
}
void solve() {
  int n, m;
  cin >> n >> m;
  vector<long long> c(n);
  for (long long &x : c) cin >> x;
  vector<vector<int>> adj(n);
  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    --a;
    --b;
    adj[b].push_back(a);
  }
  long long ans = 0;
  for (int i = 0; i < n; i++) sort(adj[i].begin(), adj[i].end());
  vector<int> sec(n);
  iota(sec.begin(), sec.end(), 0);
  sort(sec.begin(), sec.end(), [&](int i, int j) { return adj[i] < adj[j]; });
  for (int l = 0, r = 0; l < n; l = r) {
    if (adj[sec[l]].empty()) {
      ++r;
    } else {
      long long s = 0;
      while (r < n && adj[sec[l]] == adj[sec[r]]) s += c[sec[r++]];
      ans = mygcd(ans, s);
    }
  }
  cout << ans << "\n";
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int te = 1;
  cin >> te;
  for (int w = 1; w <= te; w++) {
    solve();
  }
  return 0;
}
