Problem Description: The international standard letter$/$number mapping found on the telephone is shown below. Write a program that reads a letter and displays its corresponding digit.

$12$

ABC $3$

DEF

$4$

GHI $5$

JKL $6$

MNO

$7$

PQRS $8$

TUV $9$

WXYZ

$0$

Hint: Use SWITCH statement.