#include <bits/stdc++.h>
using namespace std;
const int N = 1e4+5, M = 1e4+5, OO = 0x3f3f3f3f;
typedef long long ll;
#define PI 3.14159265358979323846
#define INF LONG_MAX
const int  MOD = 1e9+7;
ll solve (int n, deque<ll> dq) {
  ll res = 0;
  for (int i=0; i<n; i+=2) res+=dq[i];
  return res;
}
int main()
{
    int tc; cin>>tc;
    while (tc--){
      int n; cin>>n;
      deque <ll> dq;
      for (int i=0,x; i<n; ++i) cin>>x,dq.push_back(x);
      ll ans = 0;
      for (int i=0; i<n; ++i) {
        ans = max(ans,solve(n,dq));
        dq.push_back(dq.front());
        dq.pop_front();
      }
      cout<<ans<<endl;
    }
  return 0;
}

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