#include<bits/stdc++.h>
using namespace std;
int T,n,a[1005],b[1005],l,r,f[1000005];
int main(){
    scanf("%d",&T);
    for(;T;T--){
        memset(f,0,sizeof(f));
        scanf("%d",&n);
        for(int i=1;i<=n;i++)scanf("%d%d",&a[i],&b[i]);
        l=a[1];r=b[1];
        for(int i=2,p;i<=n;i++){
            if(b[i]>=l)r=min(r,b[i]);
            if(a[i]<=r)l=max(l,a[i]);
            if(b[i]<l){
                p=l-b[i];
                f[b[i]]=f[l]+p/2+p%2;
                if(a[i]<b[i])f[b[i]-1]=f[l]+(p+1)/2+(p+1)%2;
                if(l<r){
                    f[b[i]]=min(f[b[i]],f[l+1]+(p+1)/2+(p+1)%2);
                    if(a[i]<b[i])f[b[i]-1]=min(f[b[i]-1],f[l+1]+p/2+p%2+1);
                }
                l=max(a[i],b[i]-1);
                r=b[i];
            }
            else if(a[i]>r){
                p=a[i]-r;
                f[a[i]]=f[r]+p/2+p%2;
                if(a[i]<b[i])f[a[i]+1]=f[r]+(p+1)/2+(p+1)%2;
                if(l<r){
                    f[a[i]]=min(f[a[i]],f[r-1]+(p+1)/2+(p+1)%2);
                    if(a[i]<b[i])f[a[i]+1]=min(f[a[i]+1],f[r-1]+p/2+p%2+1);
                }
                l=a[i];
                r=min(a[i]+1,b[i]);
            }
        }
        printf("%d\n",min(f[l],f[r]));
    }
}