#include <iostream>

using namespace std;
long ds(long x)
{
    long s=0;
    while(x)
    {
        s=s+x%10;
        x=x/10;
    }
    return s;
}

int main()
{
    long sum=0;
    int a,b;
    std::cin>>a>>b;
    for(long i=a;i<=b;i++)
    {
        if(i%2==1)
            sum=sum+ds(i);
    }
    std::cout<<sum;
    return 0;
}