#include<bits/stdc++.h>

using namespace std;

#define dbg(x) (cout<<#x<<" = "<<(x)<<'\n')

typedef long long int lld;
const int INF = (1LL << 30) - 1;
const lld LINF = (1LL << 62) - 1;
const int dx[] = {1, -1, 0, 0};
const int dy[] = {0, 0, 1, -1};

int N;
int sol[] = {1,
             1,
             2,
             6,
             15,
             35,
             76,
             156,
             310,
             590,
             1098,
             1984,
             3515,
             6094,
             10398,
             17434,
             28837,
             47038,
             75820
            }; // OEIS ftw

int main() {
	cin.sync_with_stdio(false);

	#ifndef ONLINE_JUDGE
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
	#endif

	scanf("%d", &N);

	printf("%d\n", sol[N]);

	return 0;
}