F[a][b][c]=F[a-1][b][c]+F[a][b-1][c]+F[a][b][c-1];
a>=b>=c;

package zzz;

import java.math.BigInteger;
import java.util.Scanner;

public class Main {
	public static void main(String args[]){
		Scanner cin=new Scanner(System.in);
		BigInteger a[][][]=new BigInteger[67][76][76];
	
		a[0][0][0]=BigInteger.ONE;
		for(int i=1;i<=60;i++)
			for(int j=0;j<=i;j++){
				for(int k=0;k<=j;k++){
					a[i][j][k]=BigInteger.valueOf(0);        
					if(i>j)                           ///三个条件是并行的
						a[i][j][k]=a[i][j][k].add(a[i-1][j][k]);
				    if(j>k)                                    
						a[i][j][k]=a[i][j][k].add(a[i][j-1][k]);
				    if(k>=1)
						a[i][j][k]=a[i][j][k].add(a[i][j][k-1]);
					//System.out.println(a[i][j][k]);
				}
			}
		while(cin.hasNext()){
			int n=cin.nextInt();
			System.out.println(a[n][n][n]);
			System.out.println();
		}
		
	}
}