#include<iostream>
using namespace std;

int main() {
	long long a;
	long long b;
	long long c;
	long long d;
	double mid=1;
	long long ans=0;

	cin >> a;
	b = a / 2;
	c = a / 2;
	d = a / 2;



	if (a % 2 == 0) {
		for (int i = 0; i <= c; i++) {
			if (d - b > b) {
				for (int j = 0; j < b; j++) {
					mid = mid * (d - j);
				}
				for (int k = 0; k < b; k++) {
					mid = mid / (b - k);
				}
			}
			else {
				for (int j = 0; j < d - b; j++) {
					mid = mid * (d - j);
				}
				for (int l = 0; l < (d - b); l++) {
					mid = mid / (d - b - l);
				}
			}
			
			ans = ans + mid;
			mid = 1;

			d++;
			b--;
		}
		
	}
	if (a % 2 == 1) {
		d++;
		for (int i = 0; i <= c; i++) {
			if (d - b > b) {
				for (int j = 0; j < b; j++) {
					mid = mid * (d - j);
				}
				for (int k = 0; k < b; k++) {
					mid = mid / (b - k);
				}
			}
			else {
				for (int j = 0; j < d - b; j++) {
					mid = mid * (d - j);
				}
				for (int l = 0; l < (d - b); l++) {
					mid = mid / (d - b - l);
				}
			}
			ans = ans + mid;
			mid = 1;

			d++;
			b--;
		}
		
	}
	cout << ans;
	return 0;
}