a = input("please input a radom number\n") ##L is the largest number in a L = 0 for i in range(len(a)): #print("0") if L < int(a[i]): L = int(a[i]) #print("L is", L) B = [] #create a L length list with L empty list for i in range(L+1): B.append([]) print("B is:",B) for i in range(len(a)): B[int(a[i])].append(a[i]) print("B is:",B) A="" for i in range(len(B)): for j in range(len(B[i])): A+=B[i][j] print(A)