/* SRIJON
SINGHA
SAMANTA */
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#define nl "\n"
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define yes cout << "YES" << nl
#define no cout << "NO" << nl
#define fi first
#define sec second
#define pb push_back
#define ppb pop_back
#define pf push_front
#define ppf pop_front
#define FIO \
ios_base::sync_with_stdio(false); \
cin.tie(NULL); \
cout.tie(NULL);
const int mod = 1e9 + 7;
int32_t main()
{
FIO
ll t; cin >> t;
ll tt=t;
while (tt--)
{
ll n,k; cin>>n>>k;
if(n>=k) cout<<"0"<<nl;
else
{
ll mx=0;
ll a=k/n;
for(ll i=1;i<=sqrt(a);i++)
{
mx=max(mx,(i*(k-(i*n))));
}
cout<<mx<<nl;
}
}
return 0;
}