#include <cstdio>
int n, f[2][10010];
unsigned long long s;
void find(int d, int l) {
    if(l <= 0) return;
    if(d == n) { s++; return;}
    find(d+1, l-1);
    find(d+1, l+1);
}
int main() {
    freopen("mushroom.in","r",stdin);
    freopen("mushroom.out","w",stdout);
    scanf("%d", &n);
    //find(1, 2);
    f[1][2] = 1;
    for(int i=2; i<=n; i++)
        for(int j=1; j<=n+1; j++) {
			f[i%2][j] = f[(i+1)%2][j+1];
			if(j > 1)
                f[i%2][j] += f[(i+1)%2][j-1];
        }
	for(int i=1; i<=n+1; i++)
		s += f[n%2][i];
    printf("%lld\n", s);
    return 0;
}