#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
int main() {
	
	ios_base::sync_with_stdio(0); 
    cin.tie(0);                   
    cout.tie(0);
   int tc; cin >> tc;
   while(tc--){
   	int n, m; cin >> n >> m;
   	string s; cin >> s;
   	int sum = 0, f= 0; 
   	vector < int > ache;
   	for(int i = 0; i < n; i++){
   		if(s[i] == s[i+1] && s[i] == '1')
   		{
   			sum++;
   		}
   		else if( s[i] == '1'){
   			sum++;
   			ache.push_back(sum);
   			sum = 0;
   		}
   		
   	}
   	sort(ache.rbegin(),ache.rend());
   	ll ans = ache[0];
   	int q = ache.size();
   	for(int i = 1; i <= min(m , q - 1); i++){
   		//cout << ache[i] << " ";
   		ans += ache[i];
   	}
   	cout << ans << '\n';
   }
    
    return 0;
}