#include <iostream>

using namespace std;
int n,uc,s;
int main()
{
    cin>>n;
    s=1;
    while(n>=10)
    {
        uc=n%10;
        if(uc%2==1)
        {
            s=s*uc;
            n=n/10;
        }
        else
        {
            s=s*1;
            n=n/10;
        }
    }
    cout<<s;
        return 0;
}