#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;

#define ff              first
#define ss              second
#define int             long long
#define pb              push_back
#define mp              make_pair
#define pii             pair<int,int>
#define vi              vector<int>
#define mii             map<int,int>
#define pqb             priority_queue<int>
#define pqs             priority_queue<int,vi,greater<int> >
#define setbits(x)      __builtin_popcountll(x)
#define zrobits(x)      __builtin_ctzll(x)
#define mod             1000000007
#define inf             1e18
#define ps(x,y)         fixed<<setprecision(y)<<x
#define mk(arr,n,type)  type *arr=new type[n];
#define w(x)            int x; cin>>x; while(x--)
mt19937                 rng(chrono::steady_clock::now().time_since_epoch().count());
#define fastio          ios_base::sync_with_stdio(0); cin.tie(0);

int32_t main()
{
    fastio;
    int n;
    string s;
    cin>>s;n=s.length();
    if(n==1){cout<<"NO"<<endl;}
    int p=2,mx=1; char ch='a';
    vi hash(50,0);
    for(int i=0;i<n;i++) {
        hash[s[i]-'a']++;
        if(mx<=hash[s[i]]-'a'){
            mx=hash[s[i]-'a'];
            ch=s[i];
        }
    }
    if(mx<(n/p)){cout<<"NO"<<endl;return 0;}
    string ans(n,'a');
    for(int i=p;i<=n;i+=p) {ans[i-1]=ch;hash[ch-'a']--;}
    int j=0;
    for(int i=1;i<=n;i++)
    {
        if(i%p==0) continue;
        while(j<26 && hash[j]==0) j++;
        hash[j]--;
        char ch='a'+j;
        ans[i-1]=ch;
    }
    cout<<"YES"<<endl;
    cout<<ans<<endl;


return 0;
}