#include<bits/stdc++.h>
using namespace std;
const int N=1000005;
int n;
bitset<N>vis;
vector<int>prime;
void Prime(int n){
	vis[0]=vis[1]=1;
	for(int i=2;i<=n;i++){
		if(!vis[i]){
			prime.push_back(i);
		}
		for(auto j:prime){
			if(i*j>n)break;
			vis[i*j]=1;
			if(i%j==0)break;
		}
	}
}
signed main(){
	cin>>n;
	Prime(1000009);
	cout<<prime[n-1];
	return 0;
}