#include <iostream>
using namespace std;

long long CalcCombination(int n, int r) {
	long long** dp = new long long*[n + 1];
	for (int i = 0; i < n + 1; i++) {
		dp[i] = new long long[i + 1];
		for (int j = 0; j < i + 1; j++) {
			if (j == 0 || j == i) {
				dp[i][j] = 1;
			}
			else {
				dp[i][j] = (dp[i - 1][j - 1] + dp[i - 1][j]);
			}
		}
	}

	return dp[n][r];
}

int main() {
	int n;
	cin >> n;

	int count_one = n % 2;
	int count_two = n / 2;
	long long pattern = 0;

	while (count_two >= 0) {
		pattern += CalcCombination(count_one + count_two, count_two);
		count_one += 2;
		count_two--;
	}

	cout << pattern << endl;

	return 0;
}