function BracketCombinations(num) { 

  // code goes here  
  const factorial = (number) => {
    let k = 1
    for(let i = number; i >= 1; i--){
      k *= i;
    }
    return k
  }
  const finalresult = factorial(2 * num) / (factorial(num + 1) * factorial(num))

  return finalresult; 

}
   
// keep this function call here 
console.log(BracketCombinations(readline()));