#include
using namespace std;
#define ll long long
ll prime(ll n)
{ ll x=5000001;
ll arr[x]={0};
arr[0]=0;
arr[1]=0;
arr[2]=1;
for(ll i=3;i<x;i+=2)
arr[i]=1;
if(n==1)
return 2;
ll cnt=1;
ll i=3;
while(cnt<n)
{
for(ll j=i*i;j<x;j+=2*i)
arr[j]=0;
if(arr[i])
cnt++;
i+=2;
}
return i-2;
}
int main() {
ll n;
cin>>n;
cout<<prime(n);
return 0;
}