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  1. def primeset(n):
  2.     myset=set()
  3.     tstlist=[0]*(n+1)
  4.     for i in range(2,n+1):
  5.         if tstlist[i] == 0:
  6.             myset.add(i)
  7.             for j in range(i,n+1,i):
  8.                 tstlist[j]=1
  9.     return myset
  10.  
  11. def test(p,myset):
  12.     return all({int(str(p)[-i:]) in myset for i in range(1,min(len(str(p)),5))})
  13.  
  14. prime_set=primeset(int(input()))
  15. count=0
  16. for p in prime_set:
  17.     count+=test(p,prime_set)
  18. print(count)
Success #stdin #stdout 1.56s 9080KB
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1000000
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4184
https://ideone.com/8RoYT7
prime sieve approach for brilliant.org/prime-crimes-ii/
language:
Python (cpython 2.7.16)
created:
9 years ago
visibility:
public

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