#include <stdio.h>

int main(){
    int t,n,i,j,k,l,sort;
    scanf("%d",&t);
    int count[t];
    for(i = 0;i<t;i++){
        scanf("%d",&n);
        int a[n],b[n],diff[n];
         for(j = 0;j<n;j++){
            scanf("%d",&a[j]);
         }
          for(j = 0;j<n;j++){
            scanf("%d",&b[j]);
          }
        for(j = 0;j<n;j++){
            diff[j]=b[j]-a[j];
            for(k = 0;k<n;k++){
                for(l = k+1;l<n;l++){
                    if(diff[k]>diff[l]){
                        sort=diff[k];
                        diff[k]=diff[l];
                        diff[l]=sort;
                    }
                }
            }
        }

        if(diff[n-1]>0){
            count[i] = diff[n-1];
        }
        else{
            count[i]=0;
        }
    }
    for(i = 0;i<t;i++){
        printf("%d\n",count[i]);
    }
    return 0;
}