#include <bits/stdc++.h>
#pragma warning(disable : 4996)
using namespace std;
using ll = long long;
unsigned euclidean_gcd(unsigned a, unsigned b) {
  if (a < b) return euclidean_gcd(b, a);
  unsigned r;
  while ((r = a % b)) {
    a = b;
    b = r;
  }
  return b;
}
ll ll_gcd(ll a, ll b) {
  if (a < b) return ll_gcd(b, a);
  ll r;
  while ((r = a % b)) {
    a = b;
    b = r;
  }
  return b;
}
struct UnionFind {
  vector<ll> par;
  vector<ll> siz;
  UnionFind(ll sz_) : par(sz_), siz(sz_, 1LL) {
    for (ll i = 0; i < sz_; ++i) par[i] = i;
  }
  void init(ll sz_) {
    par.resize(sz_);
    siz.assign(sz_, 1LL);
    for (ll i = 0; i < sz_; ++i) par[i] = i;
  }
  ll root(ll x) {
    while (par[x] != x) {
      x = par[x] = par[par[x]];
    }
    return x;
  }
  bool merge(ll x, ll y) {
    x = root(x);
    y = root(y);
    if (x == y) return false;
    if (siz[x] < siz[y]) swap(x, y);
    siz[x] += siz[y];
    par[y] = x;
    return true;
  }
  bool issame(ll x, ll y) { return root(x) == root(y); }
  ll size(ll x) { return siz[root(x)]; }
};
long long modpow(long long a, long long n, long long mod) {
  if (n < 0) return 0;
  long long res = 1;
  while (n > 0) {
    if (n & 1) res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}
long long modinv(long long a, long long mod) { return modpow(a, mod - 2, mod); }
ll merge_cnt(vector<ll>& a) {
  int n = a.size();
  if (n <= 1) {
    return 0;
  }
  ll cnt = 0;
  vector<ll> b(a.begin(), a.begin() + n / 2);
  vector<ll> c(a.begin() + n / 2, a.end());
  cnt += merge_cnt(b);
  cnt += merge_cnt(c);
  int ai = 0, bi = 0, ci = 0;
  while (ai < n) {
    if (bi < b.size() && (ci == c.size() || b[bi] <= c[ci])) {
      a[ai++] = b[bi++];
    } else {
      cnt += n / 2 - bi;
      a[ai++] = c[ci++];
    }
  }
  return cnt;
}
int main() {
  string s;
  cin >> s;
  ll n = s.size();
  ll a = 0;
  ll b = 0;
  ll c = 0;
  for (int i = 0; i < n; i++) {
    if (s[i] = 'a') a++;
    if (s[i] = 'b') b++;
    if (s[i] = 'c') c++;
  }
  if (max({a, b, c}) - min({a, b, c}) > 1)
    cout << "NO" << endl;
  else
    cout << "YES" << endl;
}
