`C++`

#include <bits/stdc++.h>
#define ll long long
using namespace std;
int main() {
    ll n;
    cin>>n;
    for (ll i=2;i<=n;i++) {
        ll ok=1;
        for (ll j=2;j*j<=i;j++) {
            if (i%j==0) {
                ok=0;
                break;
            }
        }
        if (ok) cout<<i<<" ";
    }
    return 0;
}

`C`

#include <stdio.h>
#define ll long long
int main() {
    ll n;
    scanf("%d",&n);
    for (ll i=2;i<=n;i++) {
        ll ok=1;
        for (ll j=2;j*j<=i;j++) {
            if (i%j==0) {
                ok=0;
                break;
            }
        }
        if (ok) printf("%d ",i);
    }
    return 0;
}