n=['1','2','3','4','5','6','7','8']
def obr(m,stroka,k):
    st=stroka
    if st.count(n[0])>=2 and st.count(n[1])>=1 and st.count(n[2])>=1 and st.count(n[3])>=1 and  st.count(n[4])>=1 and st.count(n[5])>=1 and st.count(n[6])>=1 and st.count(n[7])>=1 and st[-1]=='1':
        print (st)
        return st
    for i in range(len(m)):
        if m[i][0]==stroka[-1]:
            k=0
            print(m,stroka,k)
            obr(m[:i]+m[i+1:],stroka+m[i][1], k)

        if m[i][1]==stroka[-1]:
            print(m,stroka,k)
            k=0
            obr(m[:i]+m[i+1:],stroka+m[i][0], k)



def nach(teleports_string):
    mas=sorted(teleports_string.split(','))
    k=0
    s=obr(mas,'1',0)

    print(s)

    #return any route from 1 to 1 over all points

    return "123456781"


nach("12,23,34,45,56,67,78,81") == "123456781"
nach("12,28,87,71,13,14,34,35,45,46,63,65") == "1365417821"
nach("12,15,16,23,24,28,83,85,86,87,71,74,56") == "12382478561"
nach("13,14,23,25,34,35,47,56,58,76,68") == "132586741"