#include <bits/stdc++.h>
using namespace std;
using ll = long long;
void solve() {
  string s;
  cin >> s;
  int moji[3];
  for (int i = 0; i < 3; i++) {
    moji[i] = 0;
  }
  for (int i = 0; i < s.length(); i++) {
    moji[s[i] - 'a']++;
  }
  if (moji[0] % 2 == 1 || moji[1] % 2 == 1 || moji[2] % 2 == 1) {
    if (moji[0] != 0 && moji[1] != 0 && moji[2] != 0) {
      cout << "YES" << endl;
    } else {
      cout << "NO" << endl;
    }
  } else {
    cout << "NO" << endl;
  }
}
int main() {
  solve();
  return 0;
}
