#include<stdio.h>
#include<stdlib.h>
typedef struct binode
       { char data;
         struct binode *lchild,*rchild;
       }BiNode;
char buf[255],*str=buf;
BiNode *d;
BiNode *makeTree()
{  BiNode *s;
   s=(BiNode*)malloc(sizeof(BiNode));
   s->data=*str++;
   s->lchild=NULL;
   s->rchild=NULL;
   if(*str=='(')
    { str++;
      if(*str!=',')
       { s->lchild=makeTree();
         if(*str==')')
          {str++;return s;}
         else
          { str++;
            s->rchild=makeTree();
          }
       }
      else
       { str++;
         s->rchild=makeTree();
       }
      str++;
    }
    return s;
}
void walkTree(BiNode *t)
{ putchar(t->data);
  if(t->lchild==NULL&&t->rchild==NULL)
     return;
  putchar('(');
  if(t->lchild!=NULL)
     walkTree(t->lchild);
  if(t->rchild!=NULL)
     { putchar(',');
       walkTree(t->rchild);
     }
  putchar(')');
}
void main()
{ printf("enter exp:");
  scanf("%s",str);
  d=makeTree();
  walkTree(d);
  putchar('\n');
}