text: #include<bits/stdc++.h>
  
  using namespace std;
  
  int main(){
      int n; cin >> n;
      int m[n][n];
      for(int i = 0; i < n; i++){
          for(int j = 0; j < n; j++){
              if(i==0 or j==0) m[i][j] = 1;
              else m[i][j] = m[i-1][j] + m[i][j-1];
          }
      }
      cout << m[n-1][n-1] << endl;
  
      return 0;
  }
  