#include <stdio.h> 
#include <conio.h> 
int a[100]; 
int f(int shu,int jie)
{
 int j,i;
 for (i=1;i<4;i++)
 {
  if (shu-i>0)
   {
    a[jie]=i;
    f(shu-i,jie+1);
   }
  if (shu-i==0)
   {
    a[jie]=i;
    for (j=1;j<jie+1;j++) printf("%d",a[j]);
     printf("\n");
    break;
   }
 }
return 1;
}
int walk(int n)
{if(n==1||n==2)
  return n;
 if(n==3)
  return 4;
 return (walk(n-1)+walk(n-2)+walk(n-3));
}
void main()
{ 
 int u; 
 clrscr(); 
 printf("Please input a number:"); 
 scanf("%d",&u); 
 f(u,1);
 printf("   all %d step", walk(u));
}