/*
time:2024/10/19

contest : http://zhengruioi.com/contest/1702
*/
#include<bits/stdc++.h>
using namespace std;
//#define map unordered_map
#define re register
#define ll long long
#define forl(i,a,b) for(re ll (i)=(a);i<=(b);(i)++)
#define forr(i,a,b) for(re ll (i)=(a);i>=(b);(i)--)
#define forll(i,a,b,c) for(re ll (i)=(a);i<=(b);(i)+=(c))
#define forrr(i,a,b,c) for(re ll (i)=(a);i>=(b);(i)-=(c))
#define pii pair<ll,ll>
#define mid ((l+r)>>1)
#define lowbit(x) (x&-x)
#define pb push_back
#define IOS ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define endl '\n'
#define QwQ return 0;
#define db long double
#define ull unsigned long long
#define lcm(x,y) (1ll*(x)/__gcd(x,y)*(y))
#define Sum(x,y) (1ll*((x)+(y))*((y)-(x)+1)/2)
#define x first
#define y second
#define aty cout<<"Yes\n";
#define atn cout<<"No\n";
#define cfy cout<<"YES\n";
#define cfn cout<<"NO\n";
#define xxy cout<<"yes\n";
#define xxn cout<<"no\n";
#define printcf(x) x?cout<<"YES\n":cout<<"NO\n";
#define printat(x) x?cout<<"Yes\n":cout<<"No\n";
#define printxx(x) x?cout<<"yes\n":cout<<"no\n";
#define maxqueue priority_queue<ll>
#define minqueue priority_queue<ll,vector<ll>,greater<ll>>
#define bug cout<<"---------------------------------------\n";
//ll pw(ll x,ll y,ll mod){if(y==0)return 1;if(x==0)return 0;ll an=1,tmp=x;while(y){if(y&1)an=(an*tmp)%mod;tmp=(tmp*tmp)%mod;y>>=1;}return an;}
template<typename T1,typename T2>bool Max(T1&x,T2 y){if(y>x)return x=y,1;return 0;}
template<typename T1,typename T2>bool Min(T1&x,T2 y){if(y<x)return x=y,1;return 0;}
ll _t_;
void _clear(){}
ll n;
struct node{
    int x,y;
}a[1000010];
bool cmp(node x,node y) {
    return x.x<y.x;
}
bool check(ll x)
{
    ll nx=-1,ny=-1,tx=-1,ty=-1;
    forl(i,1,n)
    {
        ll pd=0;
        if(nx==-1)
        {
            tx=a[i].x,
            nx=a[i].y;
            pd=1;
        }
        else
        {
            ll now=a[i].x-tx;
            if(x*now>=abs(nx-a[i].y))
            {
                tx=a[i].x,
                nx=a[i].y;
                pd=1;
            }
            else
            {
                if(ny==-1)
                {
                    ty=a[i].x,
                    ny=a[i].y;
                    pd=1;
                }
                else
                {
                    ll now=a[i].x-ty;
                    if(x*now>=abs(ny-a[i].y))
                    {
                        ty=a[i].x;
                        ny=a[i].y;
                        pd=1;
                    }
                }
            }
        }
        if(!pd)
            return 0;
    }
    return 1;
}
void solve()
{
    cin>>n;
    forl(i,1,n)
        cin>>a[i].x>>a[i].y;
    sort(a+1,a+1+n,cmp);
    ll L=0,R=4e9;
    while(L<R)
    {
        ll Mid=(L+R)/2;
        if(check(Mid))
            R=Mid;
        else
            L=Mid+1;
    }
    cout<<L<<endl;
}
int main()
{
//    freopen("tst.txt","r",stdin);
//    freopen("sans.txt","w",stdout);
    IOS;
    _t_=1;
    cin>>_t_;
    while(_t_--)
        solve();
    QwQ;
}