#include <bits/stdc++.h>

#define eb emplace_back
#define ep emplace
#define fi first
#define se second
#define in read<int>()
#define lin read<ll>()
#define rep(i, x, y) for(int i = (x); i <= (y); i++)
#define per(i, x, y) for(int i = (x); i >= (y); i--)

using namespace std;

using ll = long long;
using db = double;
using pii = pair < int, int >;
using vec = vector < ll >;
using veg = vector < pii >;

template < typename T > T read() {
	T x = 0; bool f = 0; char ch = getchar();
	while(!isdigit(ch)) f |= ch == '-', ch = getchar();
	while(isdigit(ch)) x = x * 10 + (ch ^ 48), ch = getchar();
	return f ? -x : x;
}

template < typename T > void chkmax(T &x, const T &y) { x = x > y ? x : y; }
template < typename T > void chkmin(T &x, const T &y) { x = x < y ? x : y; }

const int N = 1e6 + 10;
constexpr ll B = 1e16;

int n, K;
string num;

vec tnum;
const bool operator < (const vec &x, const vec &y) {
	//cerr << "!COMP: " << x << " " << y << endl;
	if(x.size() != y.size()) return x.size() < y.size();
	per(i, (int)x.size() - 1, 0)
		if(x[i] != y[i]) return x[i] < y[i];
	return 1;
}

void compose(vec &x) {
	vec ret;
	rep(i, 0, (int)x.size() - 1) {
		if(i % 16) ret.back() = ret.back() * 10 + x[i];
		else ret.eb( x[i]);
	} x = ret; reverse(x.begin(), x.end());
}

void depose(vec &x) {
	reverse(x.begin(), x.end());
	vec ret;
	rep(i, 0, (int)x.size() - 1) {
		rep(j, 0, 15) ret.eb( x[i] % 10 ), x[i] /= 10;
	} while(ret.size() && ret.back() == 0) ret.pop_back(); x = ret;
}

vec getp(int l, int r) {
	vec ret; l--, r--;
	rep(i, l, r) ret.eb(tnum[i]);
	compose(ret);
	//cout << l << " " << r << " " << ret[0] << endl;
	return ret;
}

vec operator * (const vec &a, const vec &b) {
	vec t(max(a.size(), b.size()) + 1, 0);
	rep(i, 0, max(a.size(), b.size())) {
		if(i < a.size()) t[i] += a[i];
		if(i < b.size()) t[i] += b[i];
		if(t[i] >= B) t[i + 1] += t[i] / B, t[i] %= B;
	} while(t.back() == 0) t.pop_back(); 
	/*cerr << "CALC: " << a << " " << b << " " << t << endl;*/ return t;
}

vec get(const vec &pot) {
	int cur = 1; vec ret;
	//for(auto v : pot) cerr << v << " "; cerr << endl;
	for(auto v : pot) {
		int l = cur, r = l + v - 1;
		//cerr << l << " " << r << " " << getp(l, r) << endl;
		ret = ret * getp(l, r);
		cur += v;
	} //cerr << "!" << ret << endl;
	return ret;
}

void solve() {
	cin >> n >> K >> num;
	//reverse(num.begin(), num.end());
	vec().swap(tnum);
	for(auto &v : num) v -= '0', tnum.eb(v);
	int len = n / (K + 1);
	vec ans; bool fl = 0;
	auto upd = [&](const vec &ret) {
		if(!fl) ans = ret, fl = 1;
		else chkmin(ans, ret);
	};
	function < bool(int, int, vec) > dfs = [&](int cur, int tot, vec pot) {
		if(tot > n) return 0;
		if(cur == K + 1 && tot == n) return 0;
		if(cur == K + 1 && n - tot > len + 1) return 0;
		if(n - tot > (len + 1) * (K + 2 - cur)) return 0;
		if(cur == K + 1) return pot.eb(n - tot), upd(get(pot)), 1;
		int ptl = 0;
		per(j, len + 1, 1) {
			pot.eb(j);
			bool tl = dfs(cur + 1, tot + j, pot);
			pot.pop_back();
			if(!tl) { if(j < len) break; } else ptl = 1;
		} return ptl;
	};
	dfs(1, 0, {}); depose(ans);
	//cerr << ct << endl;
	reverse(ans.begin(), ans.end());
	for(auto v : ans) cout << v; cout << endl;
}

int main() {
#ifdef YJR_2333_TEST
	freopen("1.in", "r", stdin);
#endif
	ios :: sync_with_stdio(false), cin.tie(0), cout.tie(0);
	int T; cin >> T;
	for(; T; T--) solve(); return 0;
}