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

using ll = long long;

void solve(int T) {
	int n, k; cin >> n >> k;
	string s; cin >> s;
	s.push_back('0');

	priority_queue<int> pq;
	int cnt = 0;
	for(auto c : s) {
		if(c == '1') cnt++;
		else {
			pq.push(cnt);
			cnt = 0;
		}
	}
	ll ans = 0;
	if(!pq.empty()) {
		ans = pq.top();
		pq.pop();
		while(!pq.empty() && k) {
			ans += pq.top();
			pq.pop();
			k--;
		}
	}

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

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
#ifdef MYPC
	cout << "==== OUTPUT ====\n";
#endif
	int t; cin >> t;
	for(int i = 1; i <= t; i++) {
		solve(i);
	}
}