n= int (raw_input())
def find_prime(n):
L = list(range(2,n + 1))
m = 0
while m < len(L):
n = m + 1
while n < len(L):
if L[n]%L[m] == 0:
del L[n]
n = n + 1
m = m + 1
return L
print( sum (find_prime(n)) )

n= int(raw_input())
s=2
if n==2:
print s
else:
for i in range(n+1):
j=i-1
while(j>1):
if i%j==0:
break
else:
j-=1
if(j==1):
s+=i
print s

【不包含n本身】

import math
n = int (raw_input())
s = sum(range(2,n))
for j in range(2,n):
for i in range(2, int(math.sqrt(j)) + 1):
if j % i == 0:
s=s-j
break
print s

10以內的素數2,3,5,7的和為17。要求計算得出任意正整數n以內的所有素數的和。