#include<iostream>
#include<cstdio>
#include<vector>
#include<algorithm>
#include<cstdlib>

int T,n;
int a[1050],b[1050];
int LL,RR,spos;
long long ans;
long long x1,x2;
int p1,p2;

inline int dist(int x,int y){return (std::abs(x-y)+1)/2;}

int main(){
    scanf("%d",&T);
    while (T--){
        scanf("%d",&n);
        for (int i=1;i<=n;i++) scanf("%d%d",&a[i],&b[i]);
        ans=x1=x2=p1=p2=0;
        LL=1,RR=1000000,spos=1;
        while (spos<=n&&std::max(a[spos],LL)<=std::min(b[spos],RR))
            LL=std::max(LL,a[spos]),RR=std::min(RR,b[spos]),spos++;
//        printf("LL=%d RR=%d\n",LL,RR);
        a[spos-1]=LL,b[spos-1]=RR;
        if (spos>n){puts("0");continue;}
        if (a[spos]>RR) p1=p2=RR;
        else p1=p2=LL;
//        printf("pos=%d\n",p1);
        for (int i=spos;i<=n;i++){
            long long nxt1=0x3f3f3f3f3f3f3f3f,nxt2=0x3f3f3f3f3f3f3f3f;
            int np1=0,np2=0;
            if ((a[i]<=p1&&p1<=b[i])||(a[i]<=p2&&p2<=b[i])) continue;
            if (a[i]==b[i]) nxt1=nxt2=std::min(dist(p1,a[i])+x1,dist(p2,a[i])+x2),np1=np2=a[i];
            else{
                if (a[i]>p1||a[i]>p2) np1=a[i],np2=a[i]+1;
                else np1=b[i]-1,np2=b[i];
                nxt1=std::min(nxt1,dist(p1,np1)+x1);
                nxt1=std::min(nxt1,dist(p2,np1)+x2);
                nxt2=std::min(nxt2,dist(p1,np2)+x1);
                nxt2=std::min(nxt2,dist(p2,np2)+x2);
            }
            x1=nxt1,x2=nxt2,p1=np1,p2=np2;
        }
        printf("%I64d\n",std::min(x1,x2));
    }
}