#include<bits/stdc++.h> using namespace std; int dp[105][105]; int main(){ int n; cin>>n; for (int i = 0;i <= n;i++){ dp[0][i] = 1; } for (int i = 1;i <= n;i++){ for (int j = i;j <= n;j++){ dp[i][j] = dp[i - 1][j]; if (i != j){ dp[i][j] += dp[i][j - 1]; } } } cout<<dp[n][n]<<endl; return 0; }