#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
LL arr[200005];int pos=0;
void init(LL n){
    arr[++pos]=n;arr[++pos]=1;
    for (LL i=2;i*i<=n;++i){
        if (!(n%i)){arr[++pos]=i;arr[++pos]=(n/i);}
    }
    sort(arr+1,arr+1+pos);
    pos=unique(arr+1,arr+1+pos)-arr-1;
}
void work(){
    LL l,r;
    scanf("%lld%lld",&l,&r);
    int ans=upper_bound(arr+1,arr+1+pos,r)-arr-1;
    if (arr[ans]<l){puts("-1");return;}
    printf("%lld\n",arr[ans]);
}
int main(){
    arr[0]=INT_MIN;
    LL x,y;int T;
    scanf("%lld%lld",&x,&y);
    init(__gcd(x,y));
    scanf("%d",&T);
    ++T;while (--T){work();}
    return 0;
}