/*
TASK:necklace
LANG:C++
*/

#include<stdio.h>
#define ull unsigned long long
int dyn[64][64];
ull solve(int n) {
	dyn[1][34] = 1;
	for(int i = 2; i <= n; ++i) {
		for(int j = 0; j < 64; ++j) {
			if(dyn[i-1][j]) {
				dyn[i][j-1] += dyn[i-1][j];
				dyn[i][j+1] += dyn[i-1][j];
			}
		}
	}
	ull res = 0;
	for(int i = 0; i < 64; ++i) {
		if(i % 3 == 0) {
			res += dyn[n][i];
		}
	}
	return res;
}

int main() {
	int n;
	scanf("%d", &n);
	printf("%llu\n", solve(n));
	return 0;
}
