#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int maxn = (int)2e5+10;
ll n, l[maxn], r[maxn];

void solve()
{
    cin >> n; ll ans = 0;
    for(int i = 1; i <= n; i++) cin >> l[i];
    for(int i = 1; i <= n; i++) cin >> r[i];
    for(int i = 1; i < n; i++) ans+=min(l[i+1], r[i]);
    cout << ans << "\n";
}

int main()
{
    ios_base::sync_with_stdio(false); cin.tie(0);
    int t = 1; cin >> t; while(t--) solve(); return 0;
}