#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define int long long
#define ull unsigned long long
int T,n,m;
const int N = 1010,INF = 1e9;
string s;
int cnt[N];

void solve() 
{
	cin >> s;
	n = s.size();
	for(int i = 0;i < n;i++)
	{
	    cnt[s[i] - 'a']++;
	}
	int flag = -1;
	for(int i = 0;i < 26;i++)
	{
	    if(cnt[i] > n / 2) 
	    {
	        flag = i;
	        break;
	    }
	}
	if(flag == -1)
	{
	    cout << "YES" << endl;
	    sort(s.begin(),s.end());
	    cout << s << endl;
	    return ;
	}
	int sum = 0,ct = 0,flag2 = -1;
	for(int i = 0;i < 26;i++)
	{
	    if(i == flag) continue;
	    if(cnt[i])
	    {
	        sum += cnt[i];
	        flag2 = i;
	        ct++;
	    }
	}
	if((ct == 1 && sum == 2) || !ct)
	{
	    cout << "NO" << endl;
	    return ;
	}
	string x;
	for(int i = 0;i < n;i++)
	{
	    if(i == n / 2)
	    {
	        x += (flag2 + 'a');
	        cnt[flag2]--;
	    }
	    else{
	        if(cnt[flag])
	        {
	            x += (flag + 'a');
	            cnt[flag]--;
	        }
	        else{
	            for(int j = 0;j < 26;j++)
	            {
	                if(cnt[j])
	                {
	                    x += (j + 'a');
	                    cnt[j]--;
	                    break;
	                }
	            }
	        }
	    }
	}
	cout << "YES" << endl;
	cout << x << endl;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    T = 1;
    while(T--)
    {
        solve();
    }
}