j.c

typedef char C;
typedef long I;
typedef struct a {
  I t, r, d[3], p[2];
} *A;

#define P printf
#define R return

#define V1(f) A f(w)A w;
#define V2(f) A f(a,w)A a,w;
#define DO(n,x) {I i=0,_n=(n);for(;i<_n;++i){x;}}


I *ma(n){
  R (I*) malloc(n*8);
}
mv(d, s, n)
I *d,*s;
{
  DO(n, d[i]=s[i]);
}

tr(r, d)
I *d;
{
  I z=1;
  DO(r,z=z*d[i]);
  R z;
}

A ga(t, r, d)
     I *d;
{
  A z = (A) ma(5 + tr(r, d));
  z->t = t, z->r = r, mv(z->d, d, r);
  R z;
}
V1(iota)
{
  I n = *w->p;
  A z = ga(0, 1, &n);
  DO(n, z->p[i]=i);
  R z;
}

V2(plus){
  I r = w->r,
    *d=w->d,
    n = tr(r, d);
  A z = ga(0, r, d);
  DO(n,
     z->p[i] = a->p[i] + w->p[i]
  );
  R z;
}

V2(from){
  I r = w->r-1,
    *d= w->d+1,
    n = tr(r, d);
  A z = ga(w->t, r, d);
  mv(z->p, w->p + (n**a->p), n);
  R z;
}
V1(box){
  A z = ga(1,0,0);
  *z->p = (I)w;
  R z;
}
V2(cat){
  I an = tr(a->r, a->d),
    wn = tr(w->r, w->d),
    n  = an + wn;
  A z = ga(w->t, 1, &n);
  mv(z->p, a->p, an);
  mv(z->p+an, w->p, wn);
  R z;
}

V2(find){}

V2(rsh){
  I r = a->r ? *a->d : 1,
    n = tr(r, a->p),
    wn= tr(w->r, w->d);
  A z = ga(w->t, r, a->p);
  mv(z->p, w->p, wn=n>wn ? wn : n);
  if(n -= wn)
    mv(z->p+wn,z->p,n);
  R z;
}
V1(sha){
  A z = ga(0, 1, &w->r);
  mv(z->p, w->d, w->r);
  R z;
}

V1(id){
  R w;
}
V1(size){
  A z = ga(0,0,0);
  *z->p = w->r ? *w->d : 1;
  R z;
}

pi(i){ P("%d ",i); }
nl(){ P("\n"); }

pr(w)A w;
{
  I r = w->r,
    *d= w->d,
    n = tr(r,d);
  DO(r, pi(d[i]));
  nl();
  if( w->t ){
    DO(n,
       P("< ");
       pr(w->p[i]))
  }
  else {
    DO(n, pi(w->p[i]));
    nl();
  }
}

C vt[] = "+{~<#,";
A(*vd[])() = { 0, plus, from, find, 0, rsh, cat},
 (*vm[])() = { 0, id, size, iota, box, sha, 0};

I st[26];
qp(a){
  R a >= 'a' && a <= 'z';
}
qv(a){
  R a < 'a';
}
A ex(e)
I *e;
{
  I a=*e;
  if(qp(a)){
    if(e[1]=='=')
      R st[a-'a'] = ex(e+2);
    a = st[ a-'a'];
  }
  R qv(a) ? (*vm[a])(ex(e+1)) : e[1] ? (*vd[e[1]])(a,ex(e+2)) : (A)a;
}

noun(c){
  A z;
  if( c<'0' || c>'9')
    R 0;
  z = ga(0,0,0);
  *z->p = c-'0';
  R z;
}

verb(c)
{
  I i = 0;
  for(; vt[i] ;)
    if(vt[i++] == c)
      R i;
  R 0;
}

I *wd( s )
C *s;
{
  I a, n = strlen(s),
    *e = ma(n+1);
  C c;
  DO(n,
     e[i] = (a = noun(c=s[i])) ?
             a :
             (a=verb(c)) ? a : c);
  e[n] = 0;
  R e;
}

main(){
  C s[99];
  while(gets(s))
    pr(ex(wd(s)));
}