#include<bits/stdc++.h>
using namespace std;
const int N=1e6+7;
int n,T,k;
string str;
vector<int> add(const vector<int> &a, const vector<int> &b) {
	vector<int> res;
	int t = 0;
	for (int i = 0; i < max(a.size(), b.size()); ++i) {
		if (i < a.size()) t += a[i];
		if (i < b.size()) t += b[i];
		res.push_back(t % 10);
		t /= 10;
	}
	while (t) {
		res.push_back(t % 10);
		t /= 10;
	}
	while (res.size() > 1 && res.back() == 0) res.pop_back();
	return res;
}
vector<int> get(const string &s) {
	int len = s.length();
	vector<int> res(len);
	for (int i = 0; i < len; ++i) {
		res[i] = s[len - i - 1] - '0';
	}
	return res;
}
int com(const vector<int> &a, const vector<int> &b) {
	if(a.size()<b.size())
		return -1;
	else if(a.size()>b.size()) return 1;
	else {
		for(int i=a.size()-1; i>=0; i--) {
			if(a[i]<b[i]) return -1;
			else if(a[i]>b[i]) return 1;
		}
	}
	return 0;
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>T;
	while(T--) {
		bool flag=true;
		cin>>n>>k;
		k++;
		cin>>str;
		vector<int>a=get(str);
		vector<int>ans;
		for (int ii=0; ii<pow(3,k-1); ii++) {
			vector<int> b;
			int tmp=ii;
			if(n%k==0) {
				for(int j=0; j<k; j++) {
					if(tmp%3==0) b.push_back(n/k);
					else if(tmp%3==1) b.push_back(n/k-1);
					else if(tmp%3==2) b.push_back(n/k+1);
					tmp/=3;
				}
			} else {
				for(int j=0; j<k; j++) {
					if(tmp%3==0) b.push_back((n+k/2-1)/k);
					else if(tmp%3==1) b.push_back((n+k/2-1)/k-1);
					else if(tmp%3==2) b.push_back((n+k/2-1)/k+1);
					tmp/=3;
				}
			}

			int summ=0;
			for(auto u:b)
				summ+=u;
			b.push_back(n-summ);
			summ=n;
			if(summ!=n)  continue;
			int pre=0;
			vector<int> nowsum;
			for(int i=0; i<k; i++) {
				string st=str.substr(pre,b[i]);
				//cout<<st<<"\n";
				vector<int> tmp =get(st);
				nowsum=add(nowsum,tmp);
				pre+=b[i];
			}
			if(flag) {
				ans=nowsum;
				flag=false;
			}
			if(com(ans,nowsum)==1) {
				ans=nowsum;
			}

		}
		for (int i = ans.size() - 1; i >= 0; --i) {
			cout << ans[i];
		}
		cout<<"\n";
	}
	return 0;
}