// Program: queue_template.cpp
// Author: 

#include <iostream>
#include <cassert>

namespace ifmp
{

  // [your code ...]

} // end namespace


int main ()
{
  ifmp::queue q;
  
  // Test push(), pop(), and front()
  char ind;
  while (std::cin >> ind) {
    assert(ind == 'a' || ind == 'b');
    switch (ind) {
      case 'a':
        // Case: input number
        int i;
        std::cin >> i;
        q.push_back(i);
        break;
      case 'b':
        // Case: output to terminal
        assert(!q.empty());
        std::cout << q.front() << " ";
        q.pop_front();
        break;
    }
  }
  std::cout << "\n";
  
  // Test empty() and back()
  std::cout << "Last element: ";
  if (!q.empty())
    std::cout << q.back() << "\n";
  else
    std::cout << "none (queue empty)\n";
  
  return 0;
}