import statistics

admins={'Python':'user123@','Java':'user@123','NodeJS':'qwer123@','ReactJS':'qwer@123'}

studentDict={'Utkarsh':[78,88,99],'Sakshi':[74,85,96],'Jyoti':[71,82,93],'Trpti':[73,81,92]}

def enterGrades():
	nameToEnter=input('Student Name: ')
	gradeToEnter=input('Grade: ')

	if nameToEnter in studentDict:
		print('Adding Grade...')
		studentDict[nameToEnter].append(gradeToEnter)
	else:
		print('Student does not exist.')
	print(studentDict)

def removeStudent():
	nameToRemove=input('Student: ')
	if nameToRemove in studentDict:
		print('Removing strudent...')
		del studentDict[nameToRemove]
	else:
		print('Student does not exist.')
	print(studentDict)

def studentAvg():
	for eachStudent in studentDict:
		gradeList=studentDict[eachStudent]
		avgGrade=statistics.mean(gradeList)
		print(eachStudent,'has an avgerage grade of',avgGrade)

def main():
	print("""
	Welcome to Grade Central

	[1]-Enter Grades
	[2]-Remove Student
	[3]-Student Avg. Grades
	[4]-Exit
	""")
	action=input('What would you like to do today?!! (Enter a Number) ')

	if action=='1':
		enterGrades()
	elif action=='2':
		removeStudent()
	elif action=='3':
		studentAvg()
	elif action=='4':
		exit()
	else:
		print('No choice given,try again')

login=input('Username: ')
passw=input('Password: ')

if login in admins:
	if admins[login]==passw:
		print('Welcome',login)
		while True:
			main()
	else:
		print('Invalid Password')

else:
	print('Invalid Username,informing administrator')