int N;
const int H = 99;

{
    vector<int> dp1; dp1.resize(H);
    rd(N); N *= 2;
    dp1[0] = 1;
    REP(i, N){
        vector<int> dp2; dp2.resize(H);
        REP(j, N){
            if (j > 0) dp2[j - 1] += dp1[j];
            if (j < H-1) dp2[j + 1] += dp1[j];
        }
        dp1.swap(dp2);
    }
    cout << dp1[0] << endl;
}