#include <setjmp.h>
#include <stdlib.h>
#include <time.h>

#define M(S,I)   (putchar ("\n "#S[((I)+1)%5]))
#define I(D)     (D<<2)%15
#define N(X,Y)   (X<0 || Y<0 || X>=a || Y>=b)
#define O(X,Y,Z) (s?X=(g=s)->x, Y=s->y, Z=s->z, s=s->n, free (g),1:0)
#define T(X,Y,Z) (A(g,1)->n=s, (s=g)->x=(X), s->y=(Y), s->z=(Z))
#define A(V,S)   (V = malloc(sizeof*V*(S)))
#define U(X,Y,Z) X+=!!(Z&10)*(-!!(Z&9)+!!(Z&6)), Y+=!!(Z&5)*(-!!(Z&9)+!!(Z&6))
#define R(L)     ((int)(((double)rand()/RAND_MAX)*(L)))

#define call(FUNC,X,Y) do { T(z+1,c,t), T(FUNC,X,Y), return(0);
#define from(FUNC,L)   sub FUNC+L:; } while (0)
#define return(R)      longjmp (j, R)
#define begin          int main(int argc,char**argv) {srand((unsigned)time(NULL)),r=setjmp(j)-1,O(z,c,t);switch(z){
#define end            }return 0;}
#define sub            case
#define endsub         return(0);break;

enum {n,E,H,W,V,F,M=7,C=9,G=11,Z=14};
int a,b,c,d,e,k,l,m,o,p,r,t,v,w,x,y,z,putchar(int);
unsigned char**u;
jmp_buf j;
struct{int x,y,z;void*n;}*f,*g,*s;

begin
  sub Z:
    x=(c%(a+H))-E, y=(c/(a+H))-E;
    M (#io,x==v&&y==w?H:x==o&&y==p?W:x==a?V:y<n&&!(x%H)?!(u[y/H][x/H]&E<<n):x<n&&!(y%H)?!(u[y/H][x/H]&E<<W):!(y%H)&&!(x%H)?!(u[y/H][x/H]&E<<V):y%H&&x%H?E:x%H?!(u[y/H][x/H]&E<<E):y%H?!(u[y/H][x/H]&E<<H):E);
    if (c<(b+E)*(a+H)-E) call (Z, c+E, t) from (Z, E);
  endsub

  sub G:
    if (l<=m) {
      d=E<<R(V), (-E<(t=t-E)) && (t=F, v=(l>m/H)*l, c=l?R(v?m-l:l):l++, x=f[c+v].x, y=f[c+v].y, v?U(x,y,d),d=I(d):(u[y][x]|=E<<V));
      v=x, w=y, U(v,w,d);
      if (!N(v,w) && !N(x,y) && u[y][x]&E<<V && !(u[w][v]&E<<V) && (t=F) && (u[y][x]|=d) && (u[w][v]|=I(d)|E<<V) ) {
        call (C,l,n) from (G, E);
        f[c=r] = f[l], f[l].x=x=v, f[l++].y=y=w;
      }
      z=G+E;
      call (G,c,t) from (G,H);
    }
  endsub

  sub C:
    if (f[c].x!=v || f[c].y!=w) call (C,c+E,t) from (C,E); else r=c; return(r+E);
  endsub

  sub M:
    u[c]=calloc (a,sizeof**u); if (c) call (M,c-E,t) from (M,E);
  endsub

  sub F:
    f[c].x = c/b, f[c].y = c%b; if (c) call (F, c-E, t) from (F, E);
  endsub
  
  sub n:
    e=(a=argc>E?atoi(argv[E]):G-E)<(b=argc>H?atoi(argv[H]):F), m = b*a, A(f, m--), A(u, b);
    call (M, b-E, n) from (n,E);
    call (F, m, n) from (n,H);
    call (G, n, E) from (n,W);
    v=e?R(a)*H:-E, w=e?-E:R(b)*H;
    o=e?R(a)*H:a*H-E, p=e?b*H-E:R(b)*H, a*=H, b*=H;
    call (Z, n, n) from (n, V);
end