#include <iostream>

using namespace std;

int main()
{
	double percent;
	char letterGrd;

	cout << " Please input percent points" << endl;
	cin >> percent;

	// determine letter grade

	if (percent >= 90)
	{letterGrd = 'A';
	    cout << "Excellent " << endl;
	}
	else
		if (percent >= 80) 
		{letterGrd = 'B';
		cout << " Good job " << endl;}
     else 
		if (percent >= 70) 
		{letterGrd = 'C';
		cout << " Good Work : Try harder" << endl;}
	 else 
		if (percent >= 50) 
		{ letterGrd = 'D';
		cout << " Do your labs " << endl;}
	 else 
	 {letterGrd = 'F';
	     cout << " Don't miss lectures " << endl;
	 }
	cout << "Letter Grade is " << letterGrd << endl;

	return 0;
}