import sys
stdin = sys.stdin

sys.setrecursionlimit(10 ** 7)

def li(): return map(int, stdin.readline().split())
def li_(): return map(lambda x: int(x) - 1, stdin.readline().split())
def lf(): return map(float, stdin.readline().split())
def ls(): return stdin.readline().split()
def ns(): return stdin.readline().rstrip()
def lc(): return list(ns())
def ni(): return int(stdin.readline())
def nf(): return float(stdin.readline())

s = ns()

acnt = s.count('a')
bcnt = s.count('b')
ccnt = s.count('c')

print("YES" if max(acnt, bcnt, ccnt) - min(acnt, bcnt, ccnt) <= 1 else "NO")