#include <bits/stdc++.h>
using namespace std;
int main() {
  long long a, b, n;
  cin >> a >> b >> n;
  map<long long, bool> A;
  map<long long, bool> B;
  for (long long i = 1; i <= sqrt(a); i++) {
    if (a % i == 0) {
      A[i] = 1;
      A[a / i] = 1;
    }
  }
  for (long long i = 1; i <= sqrt(b); i++) {
    if (b % i == 0) {
      B[i] = 1;
      B[b / i] = 1;
    }
  }
  long long M = min(a, b);
  if (M == a) {
    for (long long i = 0; i < n; i++) {
      long long R, L;
      long long d = -1;
      cin >> L >> R;
      for (auto j = A.begin(); j != A.end(); j++) {
        if (B[j->first] && j->first >= L && j->first <= R) {
          d = j->first;
        }
      }
      cout << d << endl;
    }
  } else {
    for (long long i = 0; i < n; i++) {
      long long R, L;
      long long d = -1;
      cin >> L >> R;
      for (auto j = B.begin(); j != B.end(); j++) {
        if (A[j->first] && j->first >= L && j->first <= R) {
          d = j->first;
        }
      }
      cout << d << endl;
    }
  }
  return 0;
}
