#include <bits/stdc++.h>
#define Fst first
#define Snd second
#define MP make_pair
#define ll long long
#define PII pair<int,int>
#define PIL pair<int,ll>
#define PLI pair<ll,int>
#define PLL pair<ll,ll>
#define PDD pair<double,double>
#define lint vector<int>
using namespace std;
int tac,n,m;
string s;
char str[200010];
bool operator < (lint x,lint y)
{
    if (x.size()!=y.size()) return x.size()<y.size();
    for (int i=(int)x.size()-1;i>=0;i--) if (x[i]!=y[i]) return x[i]<y[i];
    return 0;
}
bool operator > (lint x,lint y)
{
    if (x.size()!=y.size()) return x.size()>y.size();
    for (int i=(int)x.size()-1;i>=0;i--) if (x[i]!=y[i]) return x[i]>y[i];
    return 0;
}
lint operator + (lint x,lint y)
{
    if (x.size()<y.size()) swap(x,y);
    for (int i=0;i<y.size();i++) x[i]+=y[i];
    for (int i=0;i<(int)x.size()-1;i++) x[i+1]+=x[i]/10,x[i]%=10;
    if (!x.empty() && x.back()>=10) x.push_back(x.back()/10),x[(int)x.size()-2]%=10;
    return x;
}
void operator += (lint &x,lint y)
{
    if (x.size()<y.size()) swap(x,y);
    for (int i=0;i<y.size();i++) x[i]+=y[i];
    for (int i=0;i<(int)x.size()-1;i++) x[i+1]+=x[i]/10,x[i]%=10;
    if (!x.empty() && x.back()>=10) x.push_back(x.back()/10),x[(int)x.size()-2]%=10;
}
inline void OUT(lint x)
{
    if (x.empty()) printf("0");
    else for (int i=(int)x.size()-1;i>=0;i--) printf("%d",x[i]);
}
inline void Main()
{
    scanf("%d%d%s",&n,&m,str),s=str,m++; lint res(0);
    for (int i=0;i<(1<<m);i++)
    {
        if (__builtin_popcount(i)!=n%m) continue;
        lint r(0); int bk=0;
        for (int j=0;j<m;j++)
        {
            int ln=((i&(1<<j)) ? n/m+1 : n/m); lint t(0);
            //cerr <<ln<<" $$\n";
            for (int k=bk;k<bk+ln;k++) t.push_back(s[k]-'0');
            reverse(t.begin(),t.end()); r+=t; bk+=ln;
        }
        if (r>res) res=r;
    }
    OUT(res),puts("");
}
int main()
{
    scanf("%d",&tac);
    while (tac--) Main();
    return 0;
}