#include <bits/stdc++.h>
using namespace std;
long long a[100];
int main() {
  int n;
  scanf("%d", &(n));
  memset(a, 0, sizeof(a));
  a[1] = 2, a[2] = 6;
  for (int i = 3; i < 60; i++) {
    a[i] = 2 * (a[i - 1] - a[i - 2]) + a[i - 1];
  }
  printf("%I64d", (a[n]));
  return 0;
}
