#include <iostream.h>

main()
{
  int score;
  char grade;

  cout << "Score? ";
  cin >> score;

  if (score >= 80)
    grade = 'A';
  else                  // score < 80
    if (score >= 70)
      grade = 'B';
    else                // score < 70
      if (score >= 60)
        grade = 'C';
      else              // score < 60
        if (score >= 50)
          grade = 'D';
        else            // score < 50
          grade = 'F';
  cout << "Grade: " << grade << endl;

  return 0;
}