#include<bits/stdc++.h>
using namespace std;

int main()
{
   int t;
   cin >> t;
   while(t--){
   int n;
   cin >> n;
   string board;
   cin >> board;
   vector<int> one;
    int i = 0;
    while (i < n) {
        if (board[i] == '1') {
            int length = 0;
            while (i < n && board[i] == '1') {
                length++;
                i++;
            }
            one.push_back(length);
        } else {
            i++;
        }
    }
    sort(one.rbegin(), one.rend());
    int ans = 0;
    for (int j = 0; j < one.size(); j += 2) {
        ans += one[j];
    }
    cout <<ans<<endl;
   } return 0;
}