#include<bits/stdc++.h>
#ifdef Sabbir
#pragma GCC diagnostic ignored "-Wunused-variable"
#pragma GCC diagnostic ignored "-Wsign-compare"
#endif
using namespace std;
#ifdef Sabbir
#include <E:\CodeBox\TempBox\Debug\debug.h>
#else
#define dbg(x...)
#endif
#define ll                 long long
#define all(x)             (x).begin(), (x).end()
#define in(v)               for(auto &b:v)cin>>b;
#define pb                  push_back
#define inf               (long long)1e8+7
const int mx=4e5+5;

void pagol(){
    int n,k;
    cin>>n>>k;
    string s;
    cin>>s;
    priority_queue<int> pq;
    int cnt=0;
    for(int i=0;i<n;i++){
        if(s[i]=='1'){
            cnt++;
        }else{
            if(cnt){
                pq.push(cnt);
            }
            cnt=0;
        }
    }
    int ans=pq.top();
    pq.pop();
    while(k and !pq.empty()){
        ans+=pq.top();
        pq.pop();
        k--;
    }
    cout<<ans<<endl;
 
}

int32_t main() {
  ios::sync_with_stdio(0);cin.tie(0);
    int t = 1;
   cin>>t;
    while (t--) {

        pagol();
    }
    return 0;
}
//যদ্দপী, আমি তাহাতেই মুগ্ধ হইয়া গিয়াছি