#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
#include <stdio.h>
#define ll long long
#define mem(a,n) memset((a),n,sizeof (a))
void fast();
ll gcd(ll x, ll y) { return(!y ? x : gcd(y, x % y)); }
ll lcm(ll x, ll y) { return x / gcd(x, y) * y; }
int dx[]{ 1, -1, 0, 0, 1, 1, -1, -1 };
int dy[]{ 0, 0, 1, -1, 1, -1, 1, -1 };
using namespace std;
int main()
{
    //freopen("input.txt" ,"r" ,stdin);
   //freopen("output.txt" ,"w" ,stdout);
    fast();
    int t; cin >> t;
    while (t--) {
        ll n, a;
        cin >> n >> a;
        ll ans = -1;
        for (ll i = n;; i--) {
            if (gcd(i, a) == 1) { ans = i; break; }
        }
        cout << ans << "\n";
        
    }
   

    return 0;
}
void fast() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}