randomize_biased

#! /usr/bin/env python2.7

import random, sys

d = sys.stdin.readlines() # lines of data
bias = []
for i in range(len(d)):
    bias.extend([i] * (len(d) - i))

random.shuffle(bias)
seen = set()

for i in bias:
    if i in seen:
        continue
    seen.add(i)
    try:
        sys.stdout.write(d[i])
    except IOError:
        break