#include<bits/stdc++.h>
using namespace std;
int a[1005],b[1005],n;
int preL[1005],preR[1005];
int succL[1005],succR[1005];
int f[105][105];
int jump(int t,int last){
    int ret=0,x=last;
    for (int i=t-1;i;i--)
        if (x<a[i]){
            ret+=(a[i]-x+1)>>1;
            if ((a[i]-x)%2==1&&a[i]<b[i]&&succL[i]==1) x=a[i]+1;else x=a[i];
        }
        else if (x>b[i]){
            ret+=(x-b[i]+1)>>1;
            if ((x-b[i])%2==1&&a[i]<b[i]&&succR[i]==-1) x=b[i]-1;else x=b[i];
        }
    x=last;
    for (int i=t+1;i<=n;i++)
        if (x<a[i]){
            ret+=(a[i]-x+1)>>1;
            if ((a[i]-x)%2==1&&a[i]<b[i]&&succL[i]==1) x=a[i]+1;else x=a[i];
        }
        else if (x>b[i]){
            ret+=(x-b[i]+1)>>1;
            if ((x-b[i])%2==1&&a[i]<b[i]&&succR[i]==-1) x=b[i]-1;else x=b[i];
        }
    return ret;
}
int main(){
    int T=10000;scanf("%d",&T);
    while (T--){
        n=rand()%4+2;scanf("%d",&n);
        for (int i=1;i<=n;i++){
            a[i]=rand()%10+2;b[i]=rand()%10+2;
            if (a[i]>b[i]) swap(a[i],b[i]);
            scanf("%d%d",&a[i],&b[i]);
        }
        /*for (int i=0;i<=30;i++) f[0][i]=0;
        for (int i=0;i<n;i++){
            for (int j=0;j<=30;j++) f[i+1][j]=1e9;
            for (int j=a[i+1];j<=b[i+1];j++)
                for (int k=0;k<=30;k++)
                    f[i+1][j]=min(f[i+1][j],f[i][k]+(abs(j-k)+1)/2);
        }
        int ans2=1e9;
        for (int j=0;j<=30;j++) ans2=min(ans2,f[n][j]);*/
        
        for (int i=1;i<=n;i++){
            preL[i]=preR[i]=0;
            for (int j=i-1;j;j--){
                if (a[j]<=a[i]&&a[i]+1<=b[j]) continue;
                if (b[j]<=a[i]) preL[i]=-1;else preL[i]=1;
                break;
            }
            for (int j=i-1;j;j--){
                if (a[j]<=b[i]-1&&b[i]<=b[j]) continue;
                if (b[j]<=b[i]-1) preR[i]=-1;else preR[i]=1;
                break;
            }
            succL[i]=succR[i]=0;
            for (int j=i+1;j<=n;j++){
                if (a[j]<=a[i]&&a[i]+1<=b[j]) continue;
                if (b[j]<=a[i]) succL[i]=-1;else succL[i]=1;
                break;
            }
            for (int j=i+1;j<=n;j++){
                if (a[j]<=b[i]-1&&b[i]<=b[j]) continue;
                if (b[j]<=b[i]-1) succR[i]=-1;else succR[i]=1;
                break;
            }
        }
        int ans=1e9;
        for (int i=1;i<=n;i++){
            ans=min(ans,jump(i,a[i]));
            ans=min(ans,jump(i,b[i]));
        }
        int L=a[1],R=b[1];
        for (int i=2;i<=n;i++)
            L=max(L,a[i]),R=min(R,b[i]);
        if (L<=R) ans=0;
        printf("%d\n",ans);
        
        /*if (ans2!=ans){
            printf("%d %d\n",ans2, ans);
            for (int i=1;i<=n;i++,puts(""))
                for (int j=a[i];j<=b[i];j++)
                    printf("%d ",f[i][j]);
            printf("%d\n",n);
            for (int i=1;i<=n;i++)
                printf("%d %d\n",a[i],b[i]);
            return 0;
        }*/
    }
}