score = int(input("your score: "))
if score >= 90:
    print('Grade is: A+')
elif score >= 85:
    print('Grade is: A')
elif score >= 80:
    print('Grade is: A-')
elif score >= 77:
    print('Grade is: B+')
elif score >= 73:
    print('Grade is: B')
elif score >= 70:
    print('Grade is: B-')
elif score >= 67:
    print('Grade is: C+')
elif score >= 63:
    print('Grade is: C')
elif score >= 60:
    print('Grade is: C-')
elif score >= 50:
    print('Grade is: D')   
else:
    print('Grade is: E')