#include<bits/stdc++.h>

using namespace std;

#define INF 0x3f3f3f3f
#define N 6000

int t,n,a[N],b[N],m,c[N],f[N];

int main(){
    scanf("%d",&t);
    while (t--){
        scanf("%d",&n); m=0;
        for (int i=1;i<=n;++i){
            scanf("%d%d",a+i,b+i);
            c[++m]=a[i]; c[++m]=a[i]+1; c[++m]=b[i]; c[++m]=b[i]-1;
        }
        sort(c+1,c+m+1);
        memset(f,0,sizeof f);
        for (int i=1;i<=n;++i){
            for (int j=1;j<=m;++j) if (c[j]<a[i]||c[j]>b[i]) f[j]=INF;
            int f1=INF,f2=INF;
            for (int j=1;j<=m;++j){
                if (c[j]&1) f1=min(f1,f[j]-c[j]/2);
                else f2=min(f2,f[j]-c[j]/2);
                if (c[j]&1){
                    f[j]=min(f[j],min(f1+c[j]/2,f2+c[j]/2+1));
                }
                else{
                    f[j]=min(f[j],min(f1+c[j]/2,f2+c[j]/2));
                }
            }
            f1=INF,f2=INF;
            for (int j=m;j;--j){
                if (c[j]&1) f1=min(f1,f[j]+c[j]/2);
                else f2=min(f2,f[j]+c[j]/2);
                if (c[j]&1){
                    f[j]=min(f[j],min(f1-c[j]/2,f2-c[j]/2));
                }
                else{
                    f[j]=min(f[j],min(f1-c[j]/2+1,f2-c[j]/2));
                }
            }
        }
        int ans=INF;
        for (int i=1;i<=m;++i) ans=min(ans,f[i]);
        printf("%d\n",ans);
        
    }
    
    return 0;
}