# http://c...content-available-to-author-only...e.com/a/55082/34718
# Author: mbomb007
I,c=input()
I+=(c-len(I)%c)*" "
L=[]
i=0
while I:s=I[:c];L+=[[s,s[::-1]][i%2]];i+=1;I=I[c:]
print"\n".join(L)
IyBodHRwOi8vYy4uLmNvbnRlbnQtYXZhaWxhYmxlLXRvLWF1dGhvci1vbmx5Li4uZS5jb20vYS81NTA4Mi8zNDcxOAojIEF1dGhvcjogbWJvbWIwMDcKCkksYz1pbnB1dCgpCkkrPShjLWxlbihJKSVjKSoiICIKTD1bXQppPTAKd2hpbGUgSTpzPUlbOmNdO0wrPVtbcyxzWzo6LTFdXVtpJTJdXTtpKz0xO0k9SVtjOl0KcHJpbnQiXG4iLmpvaW4oTCk=