#include <iostream>
#include <algorithm>
#include <string.h>
#define MAX_LEN 100
using namespace std;
int main() {
char word[MAX_LEN];
cin>>word;
int len = strlen(word), count = 0;
std::sort(word, word+len);
cout<<word<<endl;
char curr = word[0];
bool oddThere = false, not_p = false;
for(int i = 0; i < len; i++){
if(word[i] == curr)
count++;
else{
if(count%2 != 0){
if(oddThere){
not_p = true;
}
else
oddThere = true;
}
curr = word[i];
count = 1;
}
}
if(not_p)
cout<<"NO"<<endl;
else
cout<<"YES"<<endl;
}
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