#
# See ../README.md
#

#
# Run as: bc ch-1.bc < input-file
#

while (1) {
    n = read (); if (n == 0) {break;}
    if (n < 0) {n = -n}
    #
    # Find the number of digits
    #
    d = 1
    f = 10
    while (f <= n) {
        d = d + 1
        f = f * 10
    }
    if (d % 2 == 0) {
        "even number of digits"
    } else {
        if (d < 3) {
            "too short"
        } else {
            for (q = (d + 3) / 2 - 1; q >= (d - 3) / 2; q --) {
                r = (n / (10 ^ q)) % 10
                print (r)
            }
        }
    }
    "
"
}