#include
using namespace std;
void prime(long int n)
{ int count=0;
int a[5000000]={0};
a[0]=a[1]=0;
a[2]=1;
for(long int i=3;i<=5000000;i+=2)
{
a[i]=1;
}
for(long int i=3;i<=5000000;i+=2)
{
if(a[i])
{
for(long int j=i*i;j<=5000000;j+=2*i)
a[j]=0;
}
}
for(long int i=0;i<=5000000;i++)
{
if(a[i])
{
count++;
if(count==n)
{ cout<<i;
break;
}
}
}
}
int main() {
long int n;
cin>>n;
prime(n);
return 0;
}