#include <bits/stdc++.h>
using namespace std;
const int N = 100005;
int cnt[4], n;
char s[N];
void dfs(int x, int last1, int last2) {
  if (x > n) {
    puts("YES");
    exit(0);
  }
  if (cnt[0] && last1 != 1 && last2 != 1) {
    cnt[0]--;
    dfs(x + 1, last2, 1);
    cnt[0]++;
  }
  if (cnt[1] && last2 != 2 && last1 != 2) {
    cnt[1]--;
    dfs(x + 1, last2, 2);
    cnt[1]++;
  }
  if (cnt[2] && last2 != 3 && last1 != 3) {
    cnt[2]--;
    dfs(x + 1, last2, 3);
    cnt[1]++;
  }
}
int main() {
  scanf("%s", s + 1);
  n = strlen(s + 1);
  for (int i = 1; s[i]; i++) cnt[s[i] - 'a']++;
  dfs(1, 0, 0);
  puts("NO");
}
