#! /usr/bin/env python
 
from math import *
 
def isprime(n):
    for i in [2] + [x for x in range(3, int(sqrt(n)) + 1) if x % 2 != 0]:
        if n % i == 0:
            return False
 
    return True
 
def genprimes(n):
    result = []
    for i in range(2, n):
        if isprime(i):
            result.append(i)
 
    return result
 
def answer(n, primes, pos, r):
    if r - 1 <= 1:
        return primes[pos]
 
    kk = n + primes[pos]
    if sqrt(kk) == ceil(sqrt(kk)):
        print "[{:2}] {}".format(21 - r, primes[pos])
        return answer(primes[pos], primes, pos + 1, r - 1)
 
    return answer(n, primes, pos + 1, r)
 
 
print "[ 0] 2"
print answer(2, genprimes(20000), 0, 20)

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