#include <bits/stdc++.h>
using namespace std;
int rev(int x) {
  int y = 0;
  while (x) {
    y = y * 10 + x % 10;
    x /= 10;
  }
  return y;
}
bool isprime(int x) {
  for (int i = 2; i * i <= x; i++) {
    if (x % i == 0) return 0;
  }
  return 1;
}
int main() {
  int a, b = 10;
  cin >> a;
  while (a) {
    b++;
    if (b != rev(b) && isprime(b) && isprime(rev(b))) a--;
  }
  cout << b;
  return 0;
}

### Prompt

Please formulate a CPP solution to the following problem:

qd ucyhf yi q fhycu dkcruh mxeiu huluhiu yi q tyvvuhudj fhycu dkcruh. oekh jqia yi je vydt jxu djx ucyhf.

Input

jxu ydfkj sediyiji ev q iydwbu ydjuwuh d (1 ≤ d ≤ 11184) — jxu edu-rqiut ydtun ev jxu ucyhf je vydt.

Output

ekjfkj q iydwbu dkcruh.

Examples

Input

1


Output

13

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
int rev(int x) {
  int y = 0;
  while (x) {
    y = y * 10 + x % 10;
    x /= 10;
  }
  return y;
}
bool isprime(int x) {
  for (int i = 2; i * i <= x; i++) {
    if (x % i == 0) return 0;
  }
  return 1;
}
int main() {
  int a, b = 10;
  cin >> a;
  while (a) {
    b++;
    if (b != rev(b) && isprime(b) && isprime(rev(b))) a--;
  }
  cout << b;
  return 0;
}

```