#!/usr/bin/env python3

# Challenge 121
#
# TASK #1 > Invert Bit
# Submitted by: Mohammad S Anwar
# You are given integers 0 <= $m <= 255 and 1 <= $n <= 8.
#
# Write a script to invert $n bit from the end of the binary representation of
# $m and print the decimal representation of the new binary number.
#
# Example
# Input: $m = 12, $n = 3
# Output: 8
#
# Binary representation of $m = 00001100
# Invert 3rd bit from the end = 00001000
# Decimal equivalent of 00001000 = 8
#
# Input $m = 18, $n = 4
# Output: 26
#
# Binary representation of $m = 00010010
# Invert 4th bit from the end = 00011010
# Decimal equivalent of 00011010 = 26

import sys

m, n = int(sys.argv[1]), int(sys.argv[2])
print(m ^ (1 << (n-1)))