1 #include <stdio.h>
  2 #include <stdlib.h>
  3 #include <math.h>
  4
  5
  6 int main()
  7 {
  8
  9 char *tab;
 10 int i,j,n;
 11 int max;
 12
 13 scanf("%d", &n);
 14 max = sqrt(n);
 15 tab = calloc(n, sizeof(char));
 16
 17 for(i = 2; i <=max ; i++)
 18 {
 19 if(tab[i] == 0)
 20 {
 21     for(j = i + 1; j <= n ; j++)
 22     {
 23         if(tab[j] == 1)
 24             continue;
 25         if(j % i == 0)
 26             tab[j] = 1;
 27
 28     }
 29 }
 30 }
 31 tab[5] = 0;
 32 for(i = 0; i <= n; i++)
 33 {
 34     if(tab[i] == 0)
 35         printf("%d\n", i);
 36
 37 }
 38
 39 return 0;
 40 }