function sieve(n) begin
prime = [true]*(n+1)
p = 2
while p*p <= n begin
if prime[p] then for i=p*2 to n-p+1 step p begin
prime[i] = false
end
p += 1
end
for p=2 to n then if prime[p] then print(p, " ")
end
sieve(10000)
print("\n")