package myprojects.duizhan;


import java.io.*;

public class duizhan {
int  matrix[][]=new  int[500][500];
void init()
{
    matrix[0][0]=1;
    matrix[1][0]=1;
	matrix[0][1]=0;
}	

 
 
 public  void solve()
 {   
    int  number=1;
    try{ 		
        		number=1;
    			System.out.println("please input the number:");
        		number=(int)System.in.read();
            	number=number-'0';
            	
     			for(int i=1;i<=number;i++)
					for(int j=0;j<=number;j++)
					{
						if(i>=j) 
						{
						if(j==0) matrix[i][j]=matrix[i-1][j];
						else matrix[i][j]=matrix[i-1][j]+matrix[i][j-1];
			  
						}
			
						else matrix[i][j]=0;
					}
				System.out.println(matrix[number][number]);
		}
		catch(IOException e){System.out.println(e);}
	
  }
  
  
  

 	public static void main(String args[]) 
 	{
 	    duizhan myduizhan=new duizhan();
  		myduizhan.init();
  		myduizhan.solve();
    }
}