#include<cstdio>
#include<algorithm>
#include<iostream>
using namespace std;
int a[100010],l[100010],r[100010];
int main()
{
    int cas;
    scanf("%d",&cas);
    while (cas--)
    {
        int n,cc=0;
        scanf("%d",&n);
        for (int i=1;i<=n;i++) scanf("%d%d",&l[i],&r[i]),a[++cc]=l[i],a[++cc]=r[i];
        sort(a+1,a+1+cc);
        cc=unique(a+1,a+1+cc)-a-1;
        for (int i=1;i<=n;i++)
        {
            l[i]=lower_bound(a+1,a+1+cc,l[i])-a;
            r[i]=lower_bound(a+1,a+1+cc,r[i])-a;
        }
        long long Ans=1LL<<60;
        for (int i=1;i<=cc;i++)
        {
            int nowl=a[i],nowr=a[i];
            long long ans=0;
            for (int j=1;j<=n;j++)
            {
                if (nowl>=a[l[j]]&&nowl<=a[r[j]])
                {
                    nowr=min(nowr,a[r[j]]);
                    continue;
                }
                if (nowr>=a[l[j]]&&nowr<=a[r[j]])
                {
                    nowl=max(nowl,a[l[j]]);
                    continue;
                }
                if (nowr<a[l[j]])
                {
                    int tmp=(a[l[j]]-nowr+1)/2;
                    ans+=tmp;
                    int tmpl=nowr+tmp*2-1;
                    int tmpr=nowr+tmp*2;
                    nowl=max(tmpl,a[l[j]]);
                    nowr=min(tmpr,a[r[j]]);
                    continue;
                }
                int tmp=(nowl-a[r[j]]+1)/2;
                ans+=tmp;
                int tmpl=nowl-tmp*2;
                int tmpr=nowl-tmp*2+1;
                nowl=max(tmpl,a[l[j]]);
                nowr=min(tmpr,a[r[j]]);
            }
            Ans=min(Ans,ans);
        }
        cout<<Ans<<endl;
    }
    return 0;
}