1910. Arne Saknussemm

Following the account of Jules Verne, a scrambled message written by the middle age alchemist Arne Saknussemm, and deciphered by professor Lidenbrock, started the incredible travel to the center of the Earth. The scrambling procedure used by Arne is alike the procedure given below.

1. Take a non empty message M that contains letters from the English alphabet, digits, commas, dots, quotes (i.e. ‘), spaces and line breaks, and whose last character is different than space. For example, consider the following message whose translation reads “In Sneffels’s crater descend brave traveler, and touch the center of the Earth”.

In Sneffels craterem descende audas

viator, et terrestre centrum attinges.

1. Choose an integral number 0<K≤length(M) and add trailing spaces to M such that the length of the resulting message, say M’, is the least multiple of K. For K=19 and the message above, where length(M)=74 (including the 8 spaces and the line break that M contains), two trailing spaces are added yielding the message M’ with length(M’)=76.

2. Replace all the spaces from M’ by the character _ (underscore) ; replace all the line breaks from M’ by \ (backslash), and then reverse the message. In our case:

__.segnitta_murtnec_ertserret_te_,rotaiv\sadua_ednecsed_meretarc_sleffenS_nI

1. Write the message that results from step 3 in a table with length(M’)/K rows and K columns. The writing is column wise. For the given example, the message is written in a table with 76/19=4 rows and 19 columns as follows:

1. The strings of characters that correspond to the rows of the table are the fragments of the scrambled message. The 4 fragments of Arne’s message given in step 1 are:

etmneet_t\udsmt_fS _gtuerr,asaneeasf_

.narctrtria_edrrlen si_t_seeovdec_ecenI

Write a program that deciphers non empty messages scrambled as described. The length of a message, before scrambling, is at most 1000 characters, including spaces and line breaks.