#ifndef SorahISA
#define SorahISA
#include SorahISA __FILE__ SorahISA

using ll = long long;
template<typename T>
inline string to_string(const T& x){
  stringstream ss;
  return ss<<x,ss.str();
}
struct bigN:vector<ll>{
  const static int base=1'000'000'000'000'000'000,width=18;
  bool negative;
  bigN(const_iterator a,const_iterator b):vector<ll>(a,b){}
  bigN(string s){
    if(s.empty())return;
    if(s[0]=='-')negative=1,s=s.substr(1);
    else negative=0;
    for(int i=int(s.size())-1;i>=0;i-=width){
      ll t=0;
      for(int j=max(int(0),i-width+1);j<=i;++j)
        t=t*10+s[j]-'0';
      push_back(t);
    }
    trim();
  }
  template<typename T>
    bigN(const T &x):bigN(to_string(x)){}
  bigN():negative(0){}
  void trim(){
    while(size()&&!back())pop_back();
    if(empty())negative=0;
  }
  void carry(int _base=base){
    for(size_t i=0;i<size();++i){
      if(at(i)>=0&&at(i)<_base)continue;
      if(i+1u==size())push_back(0);
      int r=at(i)%_base;
      if(r<0)r+=_base;
      at(i+1)+=(at(i)-r)/_base,at(i)=r;
    }
  }
  int abscmp(const bigN &b)const{
    if(size()>b.size())return 1;
    if(size()<b.size())return -1;
    for(int i=int(size())-1;i>=0;--i){
      if(at(i)>b[i])return 1;
      if(at(i)<b[i])return -1;
    }
    return 0;
  }
  int cmp(const bigN &b)const{
    if(negative!=b.negative)return negative?-1:1;
    return negative?-abscmp(b):abscmp(b);
  }
  bool operator<(const bigN&b)const{return cmp(b)<0;}
  bool operator>(const bigN&b)const{return cmp(b)>0;}
  bool operator<=(const bigN&b)const{return cmp(b)<=0;}
  bool operator>=(const bigN&b)const{return cmp(b)>=0;}
  bool operator==(const bigN&b)const{return !cmp(b);}
  bool operator!=(const bigN&b)const{return cmp(b)!=0;}
  bigN abs()const{
    bigN res=*this;
    return res.negative=0, res;
  }
  bigN operator-()const{
    bigN res=*this;
    return res.negative=!negative,res.trim(),res;
  }
  bigN operator+(const bigN &b)const{
    // debug("add"s, b);
    if(negative)return -(-(*this)+(-b));
    if(b.negative)return *this-(-b);
    bigN res=*this;
    if(b.size()>size())res.resize(b.size());
    for(size_t i=0;i<b.size();++i)res[i]+=b[i];
    return res.carry(),res.trim(),res;
  }
  bigN &operator+=(const bigN &b) {
      if(size() < b.size()) resize(b.size());
      for(size_t i=0;i<b.size();++i) (*this)[i]+=b[i];
      return carry(), trim(), *this;
  }
  bigN operator-(const bigN &b)const{
    // debug("minus"s, b);
    if(negative)return -(-(*this)-(-b));
    if(b.negative)return *this+(-b);
    if(abscmp(b)<0)return -(b-(*this));
    bigN res=*this;
    if(b.size()>size())res.resize(b.size());
    for(size_t i=0;i<b.size();++i)res[i]-=b[i];
    return res.carry(),res.trim(),res;
  }
  bigN &operator-=(const bigN &b) {
      for(size_t i=0;i<b.size();++i) (*this)[i]-=b[i];
      return carry(), trim(), *this;
  }
  friend istream& operator>>(istream &ss,bigN &b){
    string s;
    return ss>>s, b=s, ss;
  }
  friend ostream& operator<<(ostream &ss,const bigN &b){
    if(b.negative)ss<<'-';
    ss<<(b.empty()?0:b.back());
    for(int i=int(b.size())-2;i>=0;--i)
      ss<<setw(width)<<setfill('0')<<b[i];
    return ss;
  }
  template<typename T>
    operator T(){
      stringstream ss;
      ss<<*this;
      T res;
      return ss>>res,res;
    }
};

int len_list[10], last_list[10];
int n, k, l, r;
bigN ans, temp;
string s;
int op_cnt = 0;

void dfs(int dep, int sum = 0) {
    // debug(dep);
    // if(cnt > 1) return;
    if(dep == k + 1) {
        if(sum == n) {
            ++op_cnt;
            // debug(vector<int>(len_list, len_list + k + 1));
            if(ans.empty()) {
                int cur = 0;
                for(int i = 0; i < k+1; ++i) {
                    temp = temp + bigN(s.substr(cur, len_list[i]));
                    cur += len_list[i];
                }
                memcpy(last_list, len_list, sizeof(last_list));
            }
            else {
                int cur = 0, pos = 0;
                for(int i = 0; i < k+1; ++i) {
                    if(len_list[i] != last_list[i]) {
                        pos = i; break;
                    }
                    cur += len_list[i];
                }
                int cur_ano = cur;
                for(int i = pos; i < k+1; ++i) {
                    temp -= bigN(s.substr(cur, last_list[i]));
                    temp += bigN(s.substr(cur_ano, len_list[i]));
                    cur += last_list[i]; cur_ano += len_list[i];
                    last_list[i] = len_list[i];
                }
            }
            if(ans.empty() || ans > temp) {
                ans = temp;
            }
        }
    }
    else if (dep == 0) {
        for(int i = l; i <= r; ++i) {
            len_list[dep] = i;
            dfs(dep + 1, sum + i);
        }
    }
    else {
        for(int i = max(int(1), len_list[dep-1]-1); i <= len_list[dep-1]+1; ++i) {
            len_list[dep] = i;
            dfs(dep + 1, sum + i);
        }
    }
}

void solve() {
    cin >> n >> k;
    ans.clear();
    l = max(n / (k + 1) - 1, int(1));
    r = l + 3;
    temp.resize(1); temp[0] = 0;
    cin >> s;
    dfs(0);
    cout << ans << '\n';
}

int32_t main() {
    fastIO();
    
    int t = 1; cin >> t;
    for (int _ = 1; _ <= t; ++_) {
        // cout << "Case #" << _ << ": ";
        solve();
    }
    // debug(op_cnt);
    
    return 0;
}

#else

#ifdef local
#define _GLIBCXX_DEBUG 1
#endif
#pragma GCC optimize("Ofast", "unroll-loops")
#include <bits/stdc++.h>
using namespace std;

#define int int64_t
#define double __float80
using pii = pair<int, int>;
template <typename T> using Prior = std::priority_queue<T>;
template <typename T> using prior = std::priority_queue<T, vector<T>, greater<T>>;

// #define X first
// #define Y second
#define eb emplace_back
#define ef emplace_front
#define ee emplace
#define pb pop_back
#define pf pop_front
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
#define SZ(x) ((int)(x).size())

template <size_t D, typename T> struct Vec : vector<Vec<D-1, T>> {
    static_assert(D >= 1, "Vector dimension must be greater than zero!");
    template <typename... Args> Vec(int n = 0, Args... args) : vector<Vec<D-1, T>>(n, Vec<D-1, T>(args...)) {}
};

template <typename T> struct Vec<1, T> : vector<T> {
    Vec(int n = 0, const T& val = T()) : vector<T>(n, val) {}
};

template <class F>
inline constexpr decltype(auto) lambda_fix(F&& f) {
    return [f = std::forward<F>(f)](auto&&... args) {
        return f(f, std::forward<decltype(args)>(args)...);
    };
}

#ifdef local
#define fastIO() void()
#define debug(...) \
    _color.emplace_back("\u001b[31m"), \
    fprintf(stderr, "%sAt [%s], line %d: (%s) = ", _color.back().c_str(), __FUNCTION__, __LINE__, #__VA_ARGS__), \
    _do(__VA_ARGS__), _color.pop_back(), \
    fprintf(stderr, "%s", _color.back().c_str())
deque<string> _color{"\u001b[0m"};

template <typename T> concept is_string = is_same_v<T, string&> or is_same_v<T, const string&>;
template <typename T> concept is_iterable = requires (T _t) {begin(_t);};

template <typename T> inline void _print_err(T &&_t);
template <typename T> inline void _print_err(T &&_t) requires is_iterable<T> and (not is_string<T>);
template <size_t I = 0, typename ...U> inline typename enable_if<I == sizeof...(U), void>::type _print_err(const tuple<U...> &);
template <size_t I = 0, typename ...U> inline typename enable_if<I <  sizeof...(U), void>::type _print_err(const tuple<U...> &_t);
template <size_t I = 0, typename ...U> inline typename enable_if<I == sizeof...(U), void>::type _print_err(tuple<U...> &);
template <size_t I = 0, typename ...U> inline typename enable_if<I <  sizeof...(U), void>::type _print_err(tuple<U...> &_t);
template <typename T, typename U> ostream& operator << (ostream &os, const pair<T, U> &_tu);

inline void _do() {cerr << "\n";};
template <typename T> inline void _do(T &&_t) {_print_err(_t), cerr << "\n";}
template <typename T, typename ...U> inline void _do(T &&_t, U &&..._u) {_print_err(_t), cerr << ", ", _do(_u...);}
#else
#define fastIO() ios_base::sync_with_stdio(0), cin.tie(0)
#define debug(...) void()
#endif

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

inline int getRand(int L, int R) {
    if (L > R) swap(L, R);
    return (int)(rng() % ((uint64_t)R - L + 1) + L);
}

template <typename T, typename U> bool chmin(T &lhs, U rhs) {return lhs > rhs ? lhs = rhs, 1 : 0;}
template <typename T, typename U> bool chmax(T &lhs, U rhs) {return lhs < rhs ? lhs = rhs, 1 : 0;}

/// below are Fast I/O and _print_err templates ///

/*
/// Fast I/O by FHVirus ///
/// https://fhvirus.github.io/blog/2020/fhvirus-io/ ///

#include <unistd.h>

const int S = 65536;

int OP = 0;
char OB[S];

inline char RC() {
    static char buf[S], *p = buf, *q = buf;
    return p == q and (q = (p = buf) + read(0, buf, S)) == buf ? -1 : *p++;
}

inline int RI() {
    static char c;
    int a;
    while (((c = RC()) < '0' or c > '9') and c != '-' and c != -1);
    if (c == '-') {
        a = 0;
        while ((c = RC()) >= '0' and c <= '9') a *= 10, a -= c ^ '0';
    }
    else {
        a = c ^ '0';
        while ((c = RC()) >= '0' and c <= '9') a *= 10, a += c ^ '0';
    }
    return a;
}

inline void WI(int n, char c = '\n') {
    static char buf[20], p;
    if (n == 0) OB[OP++] = '0';
    p = 0;
    if (n < 0) {
        OB[OP++] = '-';
        while (n) buf[p++] = '0' - (n % 10), n /= 10;
    }
    else {
        while (n) buf[p++] = '0' + (n % 10), n /= 10;
    }
    for (--p; p >= 0; --p) OB[OP++] = buf[p];
    OB[OP++] = c;
    if (OP > S-20) write(1, OB, OP), OP = 0;
}

/// Fast I/O by FHVirus ///
/// https://fhvirus.github.io/blog/2020/fhvirus-io/ ///
*/

#ifdef local

template <typename T> inline void _print_err(T &&_t) {cerr << _t;}

template <typename T> inline void _print_err(T &&_t) requires is_iterable<T> and (not is_string<T>) {
    string _tmp_color = _color.back();
    ++_tmp_color[3], _color.emplace_back(_tmp_color);
    cerr << _color.back() << "[";
    for (bool _first = true; auto &_x : _t) {
        if (!_first) cerr << ", ";
        _print_err(_x), _first = false;
    }
    cerr << "]" << (_color.pop_back(), _color.back());
}

template <typename T, typename U> ostream& operator << (ostream &os, const pair<T, U> &_tu) {
    string _tmp_color = _color.back();
    ++_tmp_color[3], _color.emplace_back(_tmp_color);
    cerr << _color.back() << "(";
    _print_err(_tu.first), cerr << ", ", _print_err(_tu.second);
    cerr << ")" << (_color.pop_back(), _color.back());
    return os;
}

template <size_t I = 0, typename ...U> inline typename enable_if<I == sizeof...(U), void>::type _print_err(const tuple<U...> &) {
    cerr << ")" << (_color.pop_back(), _color.back());
}

template <size_t I = 0, typename ...U> inline typename enable_if<I <  sizeof...(U), void>::type _print_err(const tuple<U...> &_t) {
    if (!I) {
        string _tmp_color = _color.back();
        ++_tmp_color[3], _color.emplace_back(_tmp_color);
        cerr << _color.back();
    }
    cerr << (I ? ", " : "("), _print_err(get<I>(_t)), _print_err<I+1, U...>(_t);
}

template <size_t I = 0, typename ...U> inline typename enable_if<I == sizeof...(U), void>::type _print_err(tuple<U...> &) {
    cerr << ")" << (_color.pop_back(), _color.back());
}

template <size_t I = 0, typename ...U> inline typename enable_if<I <  sizeof...(U), void>::type _print_err(tuple<U...> &_t) {
    if (!I) {
        string _tmp_color = _color.back();
        ++_tmp_color[3], _color.emplace_back(_tmp_color);
        cerr << _color.back();
    }
    cerr << (I ? ", " : "("), _print_err(get<I>(_t)), _print_err<I+1, U...>(_t);
}

#endif

#endif