#include<iostream>
#include<vector>
using namespace std;
long long arr[5000011];

int main() {
    long long n;
    cin>>n;
    vector<long long> v ;
    arr[0] = 0;
    arr[1] = 0;
    for(long long i = 2; i <= 5000000; i++){
            arr[i] = 1;
          //  cout<<arr[i]<<endl;
    }


    for(long long i = 2; i < 5000000; i++){

        if(arr[i] == 1){
            for(long long j = i * i; j < 5000000; j += i ){
                arr[j] = 0;
            //  cout<<j<<endl;

            }
        }
    }
//      for(long long i = 0; i < 5000000; i++)
//         cout<<arr[i]<<endl;
//cout<<"&"<<endl;
    for(long long i = 0; i < 5000000; i++){
        if(arr[i] == 1)
            v.push_back(i);
    }
    cout<<v[n - 1]<<endl;

    return 0;
}