#include <bits/stdc++.h>
using namespace std;
vector<pair<long long, long long> > vp;
vector<long long> v;
set<long long> st;
long long ara[100][100];
map<long long, long long> mp;
long long Set(long long N, long long pos) { return N = N | (1LL << pos); }
long long reset(long long N, long long pos) { return N = N & ~(1LL << pos); }
bool check(long long N, long long pos) { return (bool)(N & (1LL << pos)); }
vector<long long> e, o;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n, i, j, p;
  for (j = 1; j <= 10; j++) ara[1][j] = 1;
  for (i = 1; i <= 10; i++) ara[i][1] = 1;
  for (i = 2; i <= 10; i++) {
    for (j = 2; j <= 10; j++) ara[i][j] = ara[i - 1][j] + ara[i][j - 1];
  }
  cin >> n;
  cout << ara[n][n] << endl;
}
