#include <bits/stdc++.h>
int main() {
  char str[100000];
  int i, a = 0, b = 0, c = 0;
  int flag = 0;
  scanf("%s", str);
  for (i = 0; flag = 0; i++) {
    switch (str[i]) {
      case 'a':
        a++;
        break;
      case 'b':
        b++;
        break;
      case 'c':
        c++;
        break;
      case '\0':
        flag = 1;
        break;
    }
  }
  if (a % 2 + b % 2 + c % 2 <= 1) {
    printf("YES");
  } else {
    printf("NO");
  }
  return 0;
}
