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limit = 800000
number_list = [False] + [True]*(limit-1)
list_len = len(number_list)
def next_prime(i):
global number_list
global list_len
x = i+1
while(x <= list_len):
if number_list[x-1] == True:
break
x += 1
return x
i = 2
while(i*i <= list_len):
x = i*i
while(x <= list_len):
number_list[x-1] = False
x += i
i = next_prime(i)
primes = set()
for i in xrange(1, limit+1):
if number_list[i-1]:
primes.add(i)
def truncatable(n):
# right truncatable
tmp = n/10
while tmp > 0:
if not tmp in primes:
return False
tmp = tmp / 10
# left truncatable
tmp = n
modulo = 10**14
while tmp > 0:
if not tmp in primes:
return False
modulo = modulo / 10
tmp = tmp % modulo
return True
result = []
for p in primes:
if truncatable(p) and p not in (2, 3, 5, 7):
result += [p]
print sum(result)
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