素数线性筛
MAXN = 110100
prime = [0 for i in range(210000)]
for i in range(2,MAXN):
if prime[i] == 0:
prime[0] += 1
prime[prime[0]] = i
j = 1
while j <= prime[0] and prime[j]<=MAXN/i:
prime[prime[j]*i] = 1
if i%prime[j] == 0:
break
j += 1
print prime[10001]