#include <stdio.h>
#include <stdlib.h>
int *p, next(int n);
int isprime(int n) {
int *q=p;
for (; *q && *q * *q <= n; q++)
if (n % *q == 0) return 0;
return 1;
}
int next(int n) {
do n++;
while (!isprime(n));
return n;
}
void main() {
int N, i;
scanf("%d", &N);

p = calloc(N, sizeof(int));
for (i=1, *p=2; i < N; i++)
p[i] = next(p[i-1]);
printf("%d\n", p[N-1]);
free(p);
}