def mkcol(cov,cost,cid,kind,pair,lab):
 return {'cov':tuple(cov),'cost':F(cost),'cid':cid,'kind':kind,'pair':pair,'lab':lab}
cols=[mkcol([1 if i==j else 0 for j in range(7)],SC[i+1],i,'s',None,None) for i in range(7)]
basis=cols[:]
NCOL=[7]
def runnode(cols,basis,a,b,typ,start_u):
 u=start_u
 basis,x,pi=opt(basis,cols)
 while True:
  L=pricing(a,b,typ,pi,u)
  u+=1
  if L is None or L[6]>=0: break
  cov=[0]*7
  for z in L[0]:
   if z!=8: cov[z-1]=1
  cost=L[6]+sum(pi[i]*cov[i] for i in range(7))
  c=mkcol(cov,cost,NCOL[0],'m',(L[0][0],L[0][1]),L)
  NCOL[0]+=1
  cols.append(c)
  basis,x,pi=opt(basis,cols)
 return u,cols,basis,x,pi