#include <iostream>
using namespace std;
#define ll long long int
void primeSieve(int *p){
for (ll i = 3; i < 500005; i += 2){
p[i] = 1;
}
for (ll i = 3; i < 500005; i += 2){
if (p[i] == 1){
for (ll j = i*i; j < 500005; j += i){
p[j] = 0;
}
}
}
p[0] = p[1] = 0;
p[2] = 1;
}
int main(){
long long n;
cin >> n;
int p[500005] = {0};
primeSieve(p);
ll count = 0;
for(int i = 0; i < 500005; i++){
if(p[i] == 1){
count++;
}
if (count == n){
cout << i << endl;
break;
}
}
return 0;
// int primeArr[500005], k = 1;
// primeArr[0] = 2;
// for (int i = 3; i < 500005; i++){
// if (p[i] == 1){
// primeArr[k] = i;
// k++;
// }
// }
// cout << primeArr[n - 1] << endl;
// return 0;
}
