题解

#include<bits/stdc++.h>
using namespace std;
bool a(int b){
for (int i = 2;i * i<= b;i++){
if (b % i == 0)
return 0;
}
return 1;
}
int main(){
int n;
cin >> n;
for (int i = 2;i <= n;i++){
if (a(i))
cout << i << " ";
}
}