#write a program that prints letter grade using the following grade table
#90 - 100  A
#89 - 80   B
#79 - 70   C
#69 - 60   D
#below 60  F

#Input
x=int(input("enter grade "))

#Calculations and Output

if(x>=90):
	print("A")
elif(x>=80):
	print("B")
elif(x>=70):
	print("C")
elif(x>=60):
	print("D")
else:
	print("F")

print("End of the program")