#
# See ../README.md
#

#
# Run as: bc ch-1.bc < input-file
#
# The input-file should end with -1
#

while (1) {
    m = read ()
    if (m == -1) {
        break
    }
    n = read ()
    p = 2 ^ (n - 1)
    b = (m / p) % 2
    if (b == 1) {
        m = m - p
    }
    if (b == 0) {
        m = m + p
    }
    m
}