#!/usr/bin/env python

# Challenge 120
#
# TASK #1 - Swap Odd/Even bits
# Submitted by: Mohammad S Anwar
# You are given a positive integer $N less than or equal to 255.
#
# Write a script to swap the odd positioned bit with even positioned bit and
# print the decimal equivalent of the new binary representation.
#
# Example
# Input: $N = 101
# Output: 154
#
# Binary representation of the given number is 01 10 01 01.
# The new binary representation after the odd/even swap is 10 01 10 10.
# The decimal equivalent of 10011010 is 154.
#
# Input: $N = 18
# Output: 33
#
# Binary representation of the given number is 00 01 00 10.
# The new binary representation after the odd/even swap is 00 10 00 01.
# The decimal equivalent of 100001 is 33.

import sys

def swap_bits(n):
    out = 0
    shift = 0
    while n > 0:
        if (n & 1) != 0:
            out |= 2 << shift
        if (n & 2) != 0:
            out |= 1 << shift
        n >>= 2
        shift += 2
    return out

n = int(sys.argv[1])
n = swap_bits(n)
print(n)
