#include <iostream>

using namespace std;

int main()
{
    int a,b,s,i,cop;
    cin>>a>>b;
    if(a%2==0)
    {
        a++;
    }
    s=0;
    for(i=a;i<=b;i=i+2)
    {
        cop=i;
        while(cop>0)
        {
            s=s+cop%10;
            cop/=10;
        }
    }
    cout << s;
    return 0;
}