Modulo the number found in the string by 26
decrypted_str += chr ( ord ( ' a ' ) + ( modulo_by_26 ( num_found_so_far ) ) ) NEW_LINE num_found_so_far = " " NEW_LINE if ( len ( num_found_so_far ) > 0 ) : NEW_LINE decrypted_str += chr ( ord ( ' a ' ) + ( modulo_by_26 ( num_found_so_far ) ) ) NEW_LINE return decrypted_str NEW_LINE