s = input()
n = {'a': 0, 'b': 0, 'c': 0}
for c in s:
    n[c] += 1

import sys
if len(s) == 1:
    print('YES')
    sys.exit(0)

min = int(len(s)/3)
val = list(n.values())
val.sort()
if len(s)%3 == 0:
    if val == [min, min, min]:
        print('YES')
    else:
        print('NO')
elif len(s)%3 == 1:
    if val == [min, min, min+1]:
        print('YES')
    else:
        print('NO')
elif len(s)%3 == 2:
    if val == [min, min+1, min+1]:
        print('YES')
    else:
        print('NO')

