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

#define FAST ios_base::sync_with_stdio(false);cin.tie(NULL);
using ll = long long;

int main() {
  FAST;
  
  int tc = 1, ti;
  cin >> tc;

  for (ti = 1; ti <= tc; ++ti) {
    int n, k, i, j, ans;
    cin >> n >> k;

    string s;
    cin >> s;

    vector<int> a;
    for (i = 0; i < n; ++i) {
      if (s[i] == '0') continue;
      for (j = i+1; j < n; ++j) {
        if (s[j] == '0') break;
      }
      a.push_back(j-i);
      i = j-1;
    }
    sort(a.rbegin(), a.rend());

    ans = 0;
    for (i = 0; i < min(k+1, (int)a.size()); ++i) {
      ans += a[i];
    }

    cout << ans << "\n";
  }

  return 0;
}