a1=[1,3,4,8,12] a2=[2,5,7,10,12,14] import copy ans=copy.copy(a1) p=0 q=0 while p<len(a1) and q<(len(a2)): if a2[q]>a1[p]: p+=1 else: ans.insert(p+q,a2[q]) q+=1 print(ans+a2[q:])