#include <iostream>
#include <fstream>

using namespace std;
int v[27],n;
int NRLIT='z'-'a'+1;
int imp;

int factorial(int x)
{
    int a=1;
    for(int i=2;i<=x;i++)
        a*=i;
    return a;
}

int main()
{
    ifstream in("iv.in");
    ofstream out("iv.out");
    char x;
    while(in>>x)
    {
        v[x-'a']++;
        n++;
    }
    for(int i=0; i<NRLIT; i++)
    {
        //cout<< (char)(i+'a')<<" "<<v[i]<<" ";
        if(v[i]%2==1)
            imp++;
    }
    if(n%2==0)
    {
        if(imp>0)
            out<<0;
        else
            out<<factorial(n/2)*2;
    }
    else if(n%2==1)
    {
        if(imp>1)
            out<<0;
        else
            out<<factorial((n-1)/2)*2;

    }
    return 0;
}