#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
using ll = long long;
using ld = long double;
#define all(x) x.begin(),x.end()
#define v(x) vector<x>
#define nl '\n'
#define fxd(x) fixed << setprecision(x)
template<class t> using ordered_set = tree<t, null_type, less<t>, rb_tree_tag, tree_order_statistics_node_update>;
template<class t> using ordered_multiset = tree<t, null_type, less_equal<t>, rb_tree_tag, tree_order_statistics_node_update>;
ll nthprime(ll n)
{
vector<bool> nums(10000000,true);
ll cnt = 0;
ll sz = nums.size() -1;
for (ll i = 2; i <= sz; i++)
{
if(nums[i])
{
cnt++;
if(cnt == n)
{
return i;
}
for (ll j = i*i; j <= sz; j+=i)
{
nums[j] = false;
}
}
}
return -1;
}
int main()
{
ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
ll n ; cin >> n;
cout << nthprime(n);
}
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