#include<bits/stdc++.h>
using namespace std;
#define maxn 1002
#define inf 1000000005
int n,m,ans,F[maxn][4],c[maxn][4];
int A[maxn],cod[maxn],L[maxn],R[maxn],sz[maxn];
int dis(int x,int y)
{
    return (abs(x-y)+1)>>1;
}
void solve()
{
    scanf("%d",&n),ans=inf;
    for(int i=1;i<=n;i++)
    {
        scanf("%d %d",&L[i],&R[i]);
        sz[i]=0;
        c[i][sz[i]++]=L[i];
        if(L[i]<R[i]) c[i][sz[i]++]=R[i];
        if(L[i]+1<R[i]) c[i][sz[i]++]=L[i]+1;
        if(L[i]+2<R[i]) c[i][sz[i]++]=R[i]-1;
    }
    for(int i=1;i<=n;i++)
      for(int k=0;k<sz[i];k++)
      {
        int x=c[i][k],dn=i;
        F[i][k]=inf;
        while(dn>=1)
        {
            if(dn==1){
                F[i][k]=0;
                break;
            }
            for(int j=0;j<sz[dn-1];j++) 
               F[i][k]=min(F[i][k],F[dn-1][j]+dis(c[dn-1][j],x));
            if(x>=L[dn-1]&&x<=R[dn-1]) --dn; 
            else   break;
        }
    }
    int l=-1,r=inf;
    for(int i=n;l<=r&&i>=1;i--)
    {
        for(int j=0;j<sz[i];j++) 
          if(c[i][j]>=l&&c[i][j]<=r)  ans=min(ans,F[i][j]);
        l=max(l,L[i]),r=min(r,R[i]);
    }
    printf("%d\n",ans);
}
int main()
{
    int tmp;
    scanf("%d",&tmp);
    for(int Cas=tmp;Cas;--Cas) solve();
    return 0;
}