View Code of Problem 610

#include<bits/stdc++.h>
#include<unordered_set>
using namespace std;

long long ka(long long m,long long n){
	long long sum=1;
	for(long long i=1;i<=n;i++){
		sum*=m;
		m--;
		sum/=i;
	}
	return sum;
}

 
int main() {
 
	long long n;
	while(cin>>n){
		cout<<(ka(2*n,n)/(n+1))<<endl;
	}
 
	return 0;
}