def poem(poem,size):
    from StringIO import StringIO
    poemsize=len(poem)
    poemnumber=poemsize/size/4
    running=True
    size=size*2
    s1=0
    s2=size
    f1=size
    f2=size*2
    s=0
    dou=","
    if poemsize==40:
        dou=",\n"
    elif poemsize==56:
        dou=",\n"
    else:
        dou=","
    while running:
        print poem[s1:f1]+dou+poem[s2:f2]+"。"
        s1=s1+size*2
        s2=s2+size*2
        f1=f1+size*2
        f2=f2+size*2
        s=s+1
        if s==poemnumber:
            running=False