A给出一个数x，B每次猜一个y，A回答B，x是否可以被y整除，求出要猜的最小次数和需要猜的数。

枚举每个素数p，可以知道如果p^k<=n，则p^k一定需要选

Sample test(s)

input

4

output

3

2 4 3

input

6

output

4

2 4 3 5

 

1 # include 
      
        2 # include 
       
         3 # include 
        
          4 # include 
         
           5 # include 
          
            6 # include 
           
             7 # include 
            
              8 # include 
             
               9 # define LL long long10 using namespace std ;11 12 int ans[1010] ;13 14 bool isp (int val )15 {16 int i ;17 if (val == 1)18 return 0 ;19 for (i = 2 ; i*i <= val ; i++)20 {21 if (val % i == 0)22 return 0 ;23 }24 return 1 ;25 26 }27 28 int main()29 {30 //freopen("in.txt","r",stdin) ;31 int n ;32 while(scanf("%d",&n ) != EOF)33 {34 int i ;35 int l = 0 ;36 if (n == 1)37 {38 printf("0\n") ;39 continue ;40 }41 42 for (i = 2 ; i <= n ; i++)43 {44 if (isp(i) == 0)45 continue ;46 int p = i ;47 while(p <= n)48 {49 ans[l] = p ;50 l++ ;51 p *= i ;52 }53 }54 printf("%d\n" , l) ;55 for (i = 0 ; i < l-1 ; i++)56 printf("%d " , ans[i]) ;57 printf("%d\n" , ans[i]) ;58 }59 60 61 62 return 0;63 }