#include <iostream>
#include <iomanip>
#include <fstream>
#include <map>

using namespace std;

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[0] << "' could not be opened." << endl;
    return 1;
  }

  map<int,int> m;
  int id, count;
  while ( ifs >> id >> count )
  {
    m[id] += count;
  }

  cout << "PID    AMOUNT" << endl;
  for ( pair<int,int> p : m )
  {
    cout << setw(7) << left << p.first
         << setw(6) << right << p.second << endl;
  }
  return 0;
}