Ответ:

a = input()

a1 = []

for i in range(len(a)):

   a1.append(a[i])

if int(a1[0]) + int(a1[1]) + int(a1[2])\

  == int(a1[3]) + int(a1[4]) + int(a1[5]):

   print('YES')

else:

   print('NO')