#include<bits/stdc++.h>
#define debug(x) cerr<<#x<<" = "<<x
#define sp <<"  "
#define el <<endl
#define fgx cerr<<"-----------------------------------"<<endl
#define LL long long
#define uint unsigned int
#define ULL unsigned long long
#define LDB long double 
#define DB double
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
using namespace std;
namespace IO{
    const int BS=(1<<23)+5; int Top=0;
    char Buffer[BS],OT[BS],*OS=OT,*HD,*TL,SS[20]; const char *fin=OT+BS-1;
    char Getchar(){if(HD==TL){TL=(HD=Buffer)+fread(Buffer,1,BS,stdin);} return (HD==TL)?EOF:*HD++;}
    void flush(){fwrite(OT,1,OS-OT,stdout),OS=OT;}
    void Putchar(char c){*OS++ =c;if(OS==fin)flush();}
    void write(int x){
        if(!x){Putchar('0');return;} if(x<0) x=-x,Putchar('-');
        while(x) SS[++Top]=x%10,x/=10;
        while(Top) Putchar(SS[Top]+'0'),--Top;
    }
    inline int read(){
        int nm=0; bool fh=1; char cw=getchar();
        for(;!isdigit(cw);cw=getchar()) fh^=(cw=='-');
        for(;isdigit(cw);cw=getchar()) nm=nm*10+(cw-'0');
        return fh?nm:-nm;
    }
} using namespace IO;
#define M 1002
#define INF 1000000005
int n,m,ans,F[M][4],c[M][4],A[M],cod[M],L[M],R[M],sz[M];
inline int dis(int x,int y){return (abs(x-y)+1)>>1;}
inline void solve(){
    n=read(),ans=INF;
    for(int i=1;i<=n;i++){
        L[i]=read(),R[i]=read(),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);
//    cod[++m]=A[i],cod[++m]=B[i];
//    sort(cod+1,cod+m+1),m=unique(cod+1,cod+m+1)-cod-1;
//    for(int i=1;i<=n;i++){
//        L[i]=lower_bound(cod+1,cod+m+1,L[i])-cod;
//        R[i]=lower_bound(cod+1,cod+m+1,R[i])-cod;
//    } memset(G,0,sizeof(G));
//    for(int i=1;i<=n)    
}
int main(){
    //freopen(".in","r",stdin);
    //freopen(".out","w",stdout);
    for(int Cas=read();Cas;--Cas) solve();
    return 0;
}