n = str(12345678)
while len(n) > 1:
    res = ""
    for i in xrange(0, len(n), 2):
        res = res + str(int(n[i]) + int(n[i+1]))
    n = res
    print res

x = str(23245)

def f(n):
    n, last = str(n), ""
    print n
    if len(n) % 2 == 1:
        last = n[-1]
        n = n[:-1]
    while len(n) > 1:
        res = ""
        for i in xrange(0, len(n), 2):
            res = res + str(int(n[i]) + int(n[i+1]))
        n = res
        print res + last
    if last:
        print int(n) + int(last)

f(12345)
f(1234)

num = '12345678'
while 1 < len(num):
    pairs = ''.join(
        str(sum(map(int, pair)))
        for pair in zip(num[::2], num[1::2]))
    num = pairs + (len(num)%2 and num[-1] or '')
    print num

num = '12345678'
while 1 < len(num):
    num = str(sum(map(int, num[:2]))) + num[2:]
    print num

num = '12345678'
while 1 < len(num):
    num = str(sum(map(int, num)))
    print num