// RandomUsername (Nikola Jovanovic)
// MindCoding 2016 Round 3
// A

#include <bits/stdc++.h>
#define DBG false
#define debug(x) if(DBG) printf("(ln %d) %s = %d\n", __LINE__, #x, x);
#define lld long long
#define ff(i,a,b) for(int i=a; i<=b; i++)
#define fb(i,a,b) for(int i=a; i>=b; i--)
#define par pair<int, int>
#define fi first
#define se second
#define mid (l+r)/2
#define INF 1000000000
#define MAXN 200

using namespace std;

int ret[14] = {0, 0, 2, 6, 18, 58, 190, 638, 2170, 7474, 25974, 90982, 320738, 1137002};

int main()
{
    int n;
    scanf("%d", &n);
    printf("%d\n", ret[n]);
    return 0;
}