#include <iostream>
#include <iomanip>
#include <vector>
#include <string>
#include <algorithm>
#include <cmath>
#include <map>
#include <unordered_map>
#include <queue>
#include <bitset>
#include <limits>

using ld = long double;
using ll = long long int;
using ul = unsigned long long int;

namespace lamlib
{
	/* constant */
	constexpr double epsilon = std::numeric_limits<double>::epsilon();

	/* math */
	template<class T> inline T abs(const T &a){ return (a>0) ? a : -a; }
	ul inline digit(const ul &num){ return static_cast<ul>(std::log10(num+epsilon))+1; }

	/* algorithm */
	ul gcd(const ul &a,const ul &b) { return (!b) ? a : gcd(b,a%b); } // NOTE: a > b

	/* string */
	inline ul same_char_count(const std::string s,const char &ch){ return std::count(std::cbegin(s),std::cend(s),ch); }
}

// std::cout << std::fixed << std::setprecision(15) << std::endl;

std::vector<bool> eratosthenes(const ul &n)
{
	std::vector<bool> prime_candidate(n,true);
	
	// 0,1は素数でない.
	prime_candidate[0] = prime_candidate[1] = false;
	
	// 約数と平方根の関係(sqrt(n))
	const ul max_n = static_cast<ul>(std::sqrt(n));
	for(ul i = 2;i < max_n;++i)
	{
		// 素数でない数の倍数は, 素数でない.
		if(!prime_candidate[i]) continue;
		for(ul j = 2;i*j < n;++j)
		{
			// iの倍数は素数でない.
			prime_candidate[i*j] = false;
		}
	}

	return prime_candidate;
}

int main(int argc,char *argv[])
{
	constexpr int num = 10000;
	const auto prime = eratosthenes(num);

	int n;
	std::cin >> n;

	int index = 0;
	int counter = 0;
	for(int i = 1;i < num;++i)
	{
		if(!prime[i]) ++counter;
		if(counter == n) { index = i; break; }
	}

	std::cout << index << std::endl;

	return 0;
}