#include <cstdio>

#define Mod 9999991
#define NMax 1005

using namespace std;

long long N, S, DP[NMax][NMax], Sum[NMax][NMax];

int main()
{
    freopen ("dirichlet.in", "r", stdin);
    freopen ("dirichlet.out", "w", stdout);
    scanf ("%lld", &N);
    DP[1][1]=DP[1][0]=1;
    Sum[1][0]=1;
    Sum[1][1]=2;
    for (int i=2; i<=N; ++i)
    {
        DP[i][0]=1;
        Sum[i][0]=1;
        for (int j=1; j<=i; ++j)
        {
            DP[i][j]=Sum[i-1][j-1]+DP[i-1][j];
            Sum[i][j]=Sum[i][j-1]+DP[i][j];
        }
    }
    printf ("%lld\n", DP[N][N]);
    return 0;
}