/*

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;

}