#include <iostream>
#include <fstream>


using namespace std;
 long long nr[20];
int sum[10];
int imp(int x){if(x<=0)return 0;
               if(x<=2)return 1;
               if(x<=4)return 4;
               if(x<=6)return 9;
               if(x<=8)return 16;
               return 25;
            }

int main()
{long long i,x,a,suma,cif,sumb,b;
long long p;

    nr[1]=25;
    p=10;
    for(i=2;i<=10;i++)
    {
        nr[i]=(i-1)*45*(p/2)+25*p;
        p*=10;
    }
    for(i=1;i<=9;i++)
        sum[i]=sum[i-1]+i;


    cin>>a>>b; a--;
    suma=imp(a%10);
    p=10;i=1;
    while(p<=a)
    {
        cif=(a/p)%10;
        suma+=cif*((a%p)+1)/2 +
              (cif>0?(sum[cif-1]*p/2) : 0) +
              cif*nr[i];
    i++;p*=10;
    }
    sumb=0;
    sumb=imp(b%10);
    p=10;i=1;
    while(p<=b)
    {
        cif=(b/p)%10;
        sumb+=cif*(((b%p)+1)/2) +
              (cif>0?(sum[cif-1]*p/2) : 0) +
              cif*nr[i];
    i++;p*=10;

    }
    cout<<sumb-suma;

}