#include<bits/stdc++.h> using namespace std; long long n,a[1005][1005]; int main() { freopen("piao.in","r",stdin); freopen("piao.out","w",stdout); cin>>n; n++; a[1][0]=1; for(int i=1;i<=n;i++) for(int j=1;j<=i;j++) a[i][j]=a[i-1][j]+a[i][j-1];//递推 cout<<a[n][n]; return 0; }