#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long int a, b, n;
  cin >> a >> b >> n;
  set<long long int> s, r, ans;
  for (long long int i = 1; i <= (sqrt(a)) + 1; ++i)
    if (a % i == 0) {
      s.insert(i);
      s.insert(a / i);
    }
  for (long long int i = 1; i <= (sqrt(b)) + 1; ++i)
    if (b % i == 0) {
      r.insert(i);
      r.insert(b / i);
    }
  set<long long int>::iterator it = s.begin();
  while (it != s.end()) {
    if (r.find(*it) != r.end()) ans.insert(*it);
    it++;
  }
  for (long long int i = 0; i <= n - 1; ++i) {
    long long int x, y;
    cin >> x >> y;
    if (ans.lower_bound(x) == ans.end())
      cout << -1 << endl;
    else if (ans.upper_bound(y) == ans.begin())
      cout << -1 << endl;
    else {
      it = ans.upper_bound(y);
      it--;
      if (*(it) >= x)
        cout << (*it) << endl;
      else
        cout << -1 << endl;
    }
  }
  return 0;
}
