3. (msg_chars.py) Write a program to tally the frequency of every letter found in a message. Testing should be case- insensitive (a and A count for the same letter). In addition to the contents of Chapter 8, you will find pages 302 and 304 helpful. Use two lists, one each for alpha and count.

Sample run:

 Enter a string: This is pretty amazing! 

Letter Freq

T 3

H 1

I 3

S 2

3

P 1

R 1

E 1

Y 1

A 2

M 1

A 1

Z 1

N 1

G 1

! 1