#include<bits/stdc++.h>
using namespace std;
vector<int>prime;
void makePrime(long n){
    prime.push_back(2);
    for(long i=3;i<=n;i+=2){
        bool chk = true;
        for(int j=0;j<prime.size() && prime[j]*prime[j] <= i;j++){
            if(i % prime[j]==0){
                chk=false;
                break;
            }
        }
        if(chk)prime.push_back(i);
    }
}
int main(){
    
    int n;
    cin >> n;
    makePrime(200000);
    if(n==1)cout << 1;
    else{
        int i=0;
        while(prime[i] < 100000)i++;
        n-=2;
        cout << 2 * prime[i*n]<<endl;
        

    }
}