x = [1,2,3,4,2,8,4,2,1,4,8,3,9,1,9]
c = x[:]

for i in range(len(x)):
    c[i] = None
    try:
        t = c.index(x[i])
    except(ValueError):
        continue
    if c[t] == x[t]:
         print(x[t])
    else:
         print("damn")