#include <bits/stdc++.h>
using namespace std;
string s;
int ca, cb, cc;
int main() {
  cin >> s;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == 'a') ca++;
    if (s[i] == 'b') cb++;
    if (s[i] == 'c') cc++;
  }
  int quot = s.size() / 3;
  if (ca >= quot && cb >= quot && cc >= quot)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
