def bezout(a,b):
     l1=[1,0,a]
     l2=[0,1,b]
     while l2[2]!=0:
         q=l1[2]//l2[2]
         l1,l2=l2,[l1[0]-q*l2[0],l1[1]-q*l2[1],l1[2]-q*l2[2]]
     return l1