欧拉计划第七题

from itertools import count
import math
import time
countNum =4
t0 = time.clock()
for i in count(11):
    sqrtNum = int(math.sqrt(i))
    flag = False
    for j in range(2,sqrtNum+1):
        if i%j ==0:
            flag=True
    if not flag:
         countNum+=1

    if countNum==10001:
        print(time.clock()-t0)
        print(i)
        break