#include <bits/stdc++.h>
using namespace std;
#define SC               scanf
#define PF               printf
#define ull              unsigned long long
#define ld               long double
#define F                first
#define S                second
#define pb               push_back
#define sort_a(a)        sort(a.begin(),a.end());
#define sort_d(a)        sort(a.rbegin(),a.rend());
#define READ(f)          freopen(f, "r", stdin)
#define WRITE(f)         freopen(f, "w", stdout)
#define rev(s)           reverse(s.begin(),s.end())
#define P(ok)            cout << (ok ? "YES\n": "NO\n")
#define __Heart__              ios_base :: sync_with_stdio(false); cin.tie(NULL);
#define ll long long
typedef pair< ll , ll>                   PII;
void solve()
{
  int n , k , cnt = 0 , Ans = 0; string s ;  cin >> n >> k >> s ;
  priority_queue <int> pq ;
  for(int i = 0 ; i < n ; i++){
    if(s[i] == '0'){
        if(cnt){
            pq.push(cnt) ;
            cnt = 0 ;
        }
    }
    else cnt++ ;
  }
  if(cnt) pq.push(cnt) ;
  if(!pq.empty()){
    Ans = pq.top() ;
    pq.pop() ;
  }
  while(!pq.empty() && k){
    Ans += pq.top() ;
    pq.pop() ;
    k-- ;
  }
  cout << Ans << "\n" ;

}
int main()
{
     __Heart__
     int t ; cin >> t ; while(t--) solve() ;
}