AproapePrime

#include <bits/stdc++.h>
#define N 100001
using namespace std;
bool prim[N+1];
int n,a[N+1],la,sol;

int main()
{
    ios_base::sync_with_stdio(false);
    cin>>n;
    memset(prim,1,sizeof(prim));
    prim[0]=0;
    prim[1]=0;
    for(int p=2;p*p<N;++p)
        if (prim[p]==1)
            for(int i=p*2;i<N;i+=p)
                prim[i]=0;
    for(int p=2;p<N;++p)
        if(prim[p])
            for(int q=2;q*p<N;++q)
                if(prim[q])
                    a[p*q]=p*q;
    for(int i=4; i<N&&la<n;++i)
        if(a[i])
            ++la,sol=a[i];
    cout<<sol;
    return 0;
}