#include <stdio.h>
int main(void)
{
int i, j;
char sieve[30+1] = {0, 0, 1};

for(i=3; i<=30; i+=2) sieve[i] = 1;

for(i=3; i*i<=30; i+=2) if(sieve[i]) for(j=i*i; j<=30; j+=i*2) sieve[j] = 0;

for(i=0; i<=30; i++) if(sieve[i]) printf("%d ", i);

return 0;
}