Exercise 1: Telephone Number Generator Standard telephone keypads contain the digits 0 through 9. The numbers 2 through 9 each have 3 letters associated with them, as is indicated by the following table: Digit LetterDigit Letter ABC DEF GHI UKL MNO PORS TUV WXYZ 6 4 5 8 9 Companies use seven letter words as a memory mnemonic for consumers of their products. For example, a seven letter word like NUMBERS would translate to 686-2377. Unfortunately, your company recently upgraded their telephone system and it cannot handle words for telephone numbers. They need a program to translate their old phone business directory which consists of seven letter words into their numeric representation. The nave approach is to use an if statement or a switch statement for comparisons. An optimized approach would explore any ype ofmathematical relationships between the values or use another programming structure to perform the same task as an if statement, but in less statements. Write a program to convert the existing phone directory into their new phone directory. That is, convert each seven letter word into its numeric equivalent based upon the chart above. The file to use for input is oldPhone.txt and the new file should be called newPhone.txt