#include<bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
#define loop(i,s,n) for(int i=s;i<n;i++)
#define all(in) in.begin(), in.end()
#define rep(i,n) for(int i=0;i<n;i++)
#define loop(i,s,n) for(int i=s;i<n;i++)
#define all(in) in.begin(), in.end()
#define MP make_pair
#define INF (sizeof(int) == 4 ? 1e9:1e18)
#define EPS 0.0000000001
using namespace std;
template<class T, class S> void cmin(T &a, const S &b) { if (a > b)a = b; }
template<class T, class S> void cmax(T &a, const S &b) { if (a < b)a = b; }
template<typename Head, typename Value> auto vectors(const Head &head, const Value &v) { return vector<Value>(head, v); }
template<typename Head, typename... Tail> auto vectors(Head x, Tail... tail) { auto inner = vectors(tail...); return vector<decltype(inner)>(x, inner); }
template<class T> void join(T a){int b=0;for(auto itr :a){if(b++!=0)cout << " "; cout << itr;} }
using ll  = long long;
using ld  = long double;
using pii = pair<int,int>;
using piii = pair<int,pii>;
int W,H;
int dx[]={0,0,1,-1}, dy[]={1,-1,0,0};
bool valid(int x,int y){return (0<=x&&x<W)&&(0<=y&&y<H);}
#define int ll
signed main(){
    string s; cin >> s;
    int n = (int)s.size();
    map<char,int>mp;
    rep(i,n) mp[s[i]]++;
    int a = mp['a'];
    int b = mp['b'];
    int c = mp['c'];
    int dif = abs(a-b)+abs(a-c);
    if(dif <= 2)return puts("YES")*0;
    cout << "NO" << endl;
}

