/*
code for computing nth catalan number
*/
#include<stdio.h>
long int factorial(int x)    //long int for more than 10 factorial
{
     int i;
     long int fac;   //fac stores x factorial  
     fac=x;
     for(i=1;i<x;i++)    //loop to calculate x factorial
     {
        fac=fac*(x-i);
     }
     return fac;   //returning x factorial
}
int main()
{
    long int f1,f2,f3;  //long int for more than 10 factorial
    int n;
    float C;    //C is catalan number for n;
    scanf("%d",&n);
    f1=factorial(2*n);
    f2=factorial(n+1);
    f3=factorial(n);
    C=f1/(f2*f3);   //formula for catalan number for n
    printf("%0.2f",C);
    return 0;
}