#include <iostream>
#include <fstream>

#include <algorithm>
#include <random>
#include <vector>

using namespace std;

class Wordfeud_Pool
{
public:
  Wordfeud_Pool(istream& is) : pool{}
  {
    char c;
    int count;
    while ( is >> c >> count )
    {
      for (int i{}; i < count; ++i )
        pool.push_back(c);
    }
    random_device rnd;
    shuffle( begin(pool), end(pool), rnd);
  }

  int size() const { return pool.size(); }
  
  char draw()
  {
    char c = pool.back();
    pool.pop_back();
    return c;
  }
  
private:
  vector<char> pool;  
};

int main(int argc, char* argv[])
{
  if ( argc != 2 )
  {
    cerr << "Usage: " << argv[0] << " FILE" << endl;
    return 1;
  }

  ifstream ifs{argv[1]};
  if ( ! ifs )
  {
    cerr << "Error: '" << argv[1] << "' can not be opened!" << endl;
    return 1;
  }

  Wordfeud_Pool pool(ifs);
  int count;
  
  while ( pool.size() > 0 && cin >> count )
  {
    if ( count > pool.size() )
      count = pool.size();
    
    for (int i{}; i < count; ++i )
    {
      cout << pool.draw();
    }
    cout << endl;
  }
  
  return 0;
}