576A - Vasya and Petya's Game - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;
bool check(long long int x)
{
   long long int cnt=0;
	    for(long long int p=2;p*p<=x;p++)
	    {
	        if(x%p==0)
	        {
	            while(x%p==0)x/=p;
	            if(x>1)return 0;
	        }
	    }
	    return 1;
}
int main()
{
    vector<long long int> v;
	long long int n;
	cin>>n;
	for(int i=2;i<=n;i++)
	{
	    if(check(i))v.push_back(i);
	}
	cout<<v.size()<<endl;
	for(auto t:v) 
	{
	    cout<<t<<" ";
	}
	return 0;
}