#include <iostream>
#include <stdlib.h>

using namespace std;

int main()
{
	int number, mark;
	char grade;

	cout << "Number of assignments done=";
	cin >> number;
 	cout << "Examination mark=";
	cin >> mark;

	if ((mark >= 30) && (number >= 6))
		grade='A';
	else if ((mark >= 30) && (number < 6))
		grade='B';
	else if ((mark < 30) && (number >= 6))
		grade='C';
	else
		grade='F';
  
	cout << "Grade=" << grade << endl;

	system("PAUSE");	
	return 0;
}