fillchar(map,sizeof(map),0);
map[x1,y1]←1；
for i←x1+1 to x2 do
  for j←1 to m do
     map[i,j]←map[i-1,j-2]+map[i-1,j+2]+map[i-2,j-1]+map[i-2,j+1];
writeln(map[x2,y2]);