#include <bits/stdc++.h>
using namespace std;
int a[1100],b[1100];
int mp[1000100];
int bak[4100];
int dx[4100];
int dp[1010][4010];
const int inf=0x3f3f3f3f;
int work(){
    int n;
    scanf("%d",&n);
    int cnt=0;
    for(int i=0;i<n;i++){
        scanf("%d%d",a+i,b+i);
        dx[cnt++]=a[i];
        if(a[i]!=b[i]){
            dx[cnt++]=b[i];
            if(a[i]+1!=b[i]){
                dx[cnt++]=a[i]+1;
                if(a[i]+1!=b[i]-1){
                    dx[cnt++]=b[i]-1;
                }
            }
        }
    }
    sort(dx,dx+cnt);
    int cur=-1,v=-1;
    for(int i=0;i<cnt;i++){
        if(dx[i]!=cur){
            cur=dx[i];v++;
            bak[v]=dx[i];
            mp[dx[i]]=v;
        }
    }
    cnt=v+1;
    memset(dp,0x3f,sizeof dp);
    for(int i=mp[a[0]];i<=mp[b[0]];i++)dp[0][i]=0;
    for(int j=1;j<n;j++){
        int lp1=-1,lv1=inf,lp0=-1,lv0=inf;
        for(int i=0;i<cnt;i++){
            int re=bak[i];
            if(re&1){
                int x=(bak[i]-bak[lp1])/2+lv1;
                int y=dp[j-1][i];
                if(y<x){
                    lp1=i;
                    lv1=y;
                }
            }else{
                int x=(bak[i]-bak[lp0])/2+lv0;
                int y=dp[j-1][i];
                if(y<x){
                    lp0=i;
                    lv0=y;
                }
            }
            if(mp[a[j]]<=i&&i<=mp[b[j]]){
                int x=(bak[i]-bak[lp1])/2+(bak[i]-bak[lp1])%2+lv1;
                x=min(x,(bak[i]-bak[lp0])/2+(bak[i]-bak[lp0])%2+lv0);
                dp[j][i]=x;
                //printf("%d %d %d |%d |%d| %d\n",j,i,x,bak[lp0],bak[lp1],bak[i]-bak[lp0]);
            }
        }
        
        
        lp1=-1,lv1=inf,lp0=-1,lv0=inf;
        for(int i=cnt-1;i>=0;i--){
            int re=bak[i];
            if(re&1){
                int x=(bak[lp1]-bak[i])/2+lv1;
                int y=dp[j-1][i];
                if(y<x){
                    lp1=i;
                    lv1=y;
                }
            }else{
                int x=(bak[lp0]-bak[i])/2+lv0;
                int y=dp[j-1][i];
                if(y<x){
                    lp0=i;
                    lv0=y;
                }
            }
            if(mp[a[j]]<=i&&i<=mp[b[j]]){
                int x=(bak[lp1]-bak[i])/2+ (bak[lp1]-bak[i])%2 +lv1;
                x=min(x,(bak[lp0]-bak[i])/2+ (bak[lp0]-bak[i])%2+lv0);
                x=min(x,dp[j][i]);
                dp[j][i]=x;
            }
        }
    }
    int mn=inf;
    for(int i=mp[a[n-1]];i<=mp[b[n-1]];i++)mn=min(mn,dp[n-1][i]);
    
    /*for(int j=0;j<cnt;j++)printf("%d ",bak[j]);
    puts("");
    for(int i=0;i<n;i++){
        for(int j=0;j<cnt;j++){
            printf("%d ",dp[i][j]);
        }
        puts("");
    }*/
    
    printf("%d\n",mn);
    return 0;
}
int main(){
    int T;
    scanf("%d",&T);
    while(T--)work();
}