#include <iostream>
#include <fstream>

using namespace std;
int a,b;
    ofstream fout("simpla.out");
void Citire()
{
    ifstream fin("simpla.in");
    fin>>a>>b;
    fin.close();
}
void Rezolvare()
{
    int i,j=b,nr=0,s,d;
    for( i=a;i<=j;i++)
    {   s=0;
       d=i;
           while(d)
            {
                s=s+d%10;
                d=d/10;
            }
        d=j;
        if(s%2==0)
            nr++;
        while(d)
            {
                s=s+d%10;
                d=d/10;
            }
        if(s%2==0)
            nr++;
    }
    fout<<nr<<"\n";
}
int main()
{
    Citire();
    Rezolvare();
    return 0;
}