#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long int
#define endl '\n'
typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> pbds; // find_by_order, order_of_key
#define all(v) v.begin(), v.end()
#define yes cout << "YES" << endl        
#define no cout << "NO" << endl          
#define M 1000000007                     
#define lcm(a, b) a *b / gcd(a, b)       
#define memz(a) memset(a, 0, sizeof(a))  
#define memn(a) memset(a, -1, sizeof(a)) 
ll dx[]={1,0,-1,0,1,-1,-1,1};
ll dy[]={0,1,0,-1,1,1,-1,-1};

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    ll tst;
    cin>>tst;
    for(ll test=1;test<=tst;test++)
    {
        //cout<<"Case "<<test<<": ";
        ll n,k;
        cin>>n>>k;
        bool flag=false;
        string s;
        cin>>s;
        vector<ll>x;
        ll c=0;
        for(auto u:s)
        {
            if(u=='1')
            {
                if(flag==false)
                {
                    c=1;
                    flag=true;
                }
                else
                {
                    c++;
                }
            }
            else
            {
                flag=false;
                if(c>0)
                {
                    x.push_back(c);
                    c=0;
                }
            }
        }
        if(c>0)x.push_back(c);
        // for(auto u:x)cout<<u<<" ";
        // cout<<endl;
        k++;
        sort(all(x));
        ll ans=0;
        ll p=x.size()-1;
        while(k--)
        {
            ans+=x[p];
            p--;
            if(p<0)break;
        }
        cout<<ans<<endl;
    }
}