(Convert letter grade to number)

Write a program that prompts the user to enter a letter grade A/a, B/b, C/c, D/d, or F/f and displays its corresponding numeric value 4, 3, 2, 1, or 0.

Sample Run 1

Enter a letter grade: B

The numeric value for grade B is 3

Sample Run 2

Enter a letter grade: b

The numeric value for grade b is 3

Sample Run 3

Enter a letter grade: T

T is an invalid grade

In python.