https://www.pbinfo.ro/probleme/3254/prod-pi

#include <iostream>
using namespace std;

int main()
{
    int n,min=10,max=-1;
    cin>>n;
    while(n)
    {
        if(n%2==0 && n%10>max) max=n%10;
        if(n%2==1 && n%10<min) min=n%10;
        n=n/10;
    }
    cout<<min*max;
    return 0;
}