#include <bits/stdc++.h>
using namespace std;
 
// Speed
#define fast_io ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
 
// Typedefs
#define int long long
#define pb push_back
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((int)(x).size())
#define endl '\n'
 
// Loops
#define rep(i,a,b) for(int i=a;i<b;++i)
#define each(x, a) for (auto &x : a)
 
void solve() {
    int n;
    cin>>n;
    vector<int> a(n);
    vector<int> b(n);
    rep(i,0,n) cin>>a[i];
    rep(i,0,n) cin>>b[i];
    int sum=0;
    rep(i,0,n){
    	sum=sum+max(sum-a[i],b[i]-sum);
    }
    cout<<sum<<endl;
}
 
int32_t main() {
    fast_io;
    int t;
    cin >> t;
    while (t--) solve();
    return 0;
}
 

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

MwozCjQgLTggLTEKLTMgLTcgMAo1Ci0zIDEgMCA3IDEKLTUgMyAtMSA0IC01CjUKLTcgNyA1IDQgOQotOSAtMyAzIDIgMgo=

3
3
4 -8 -1
-3 -7 0
5
-3 1 0 7 1
-5 3 -1 4 -5
5
-7 7 5 4 9
-9 -3 3 2 2