#include <bits/stdc++.h>

using namespace std;
#define int long long int
int32_t main() {
    int t, n, k;
    cin >> t;
    while (t--) {
        cin >> n >> k;
        string s;
        cin >> s;

        vector < int > v;
        int c = 0;
        for (int i = 0; i < n; i++) {
            if (s[i] == '1') {
                c++;
            }
            else {
                v.push_back(c);
                c = 0;
            }
        }
        if (c) {
            v.push_back(c);
        }
        sort(rbegin(v),rend(v));
        int res = 0;
        for (int i = 0; i < min(k + 1, (int)v.size()); i++) {
            res += v[i];
        }
        cout << res << "\n";
    }
    // your code goes here
}