#include <bits/stdc++.h>

using namespace std;

void solve(int cs) {
  int n, k;
  cin >> n >> k;
  multiset<int> S;
  string s; cin >> s;
  int ones = 0;
  for (auto &c : s) {
    if (c == '1') ones += 1;
    else if (ones) S.insert(ones), ones = 0;
  }
  if (ones) S.insert(ones);
  int ans = 0;
  while (k >= 0 && S.size() > 0) {
    ans += *S.rbegin();
    S.erase(--S.end());
    --k;
  }
  cout << ans << "\n";
}

int32_t main() {
  ios::sync_with_stdio(!cin.tie(0));
  int t = 1;
  cin >> t;
  for (int i = 1; i <= t; ++i) {
    solve(i);
  }
  return 0;
}