#include <iostream>

using namespace std;

#define lung unsigned long long

lung nr(lung x)
{
    lung res=0;

    lung sum=0,aux=x,p=1;
    aux=x/10;

    int i,uc,q;

    while(aux)
    {
        aux/=10;
        p*=10;
        sum+=(aux*p);
    }

    res=res + sum*45;
    res=res + (sum+x/10)*25;

    uc=x%10;
    for(i=1;i<=uc;i+=2) res+=i;

    p=5;
    q=(x%10+1)/2;
    for(aux=x/10;aux;aux/=10,p*=10)
    {
        uc=aux%10;
        for(i=1;i<uc;++i) res+=1ull*i*p;
        res+=1ull*uc*q;
        q=q*(uc+1);
    }
    return res;
    uc=x/10%10;
    p=5;
    for(i=1;i<uc;++i) res+=1ull*i*p;
    res+=1ull*uc*((x%10+1)/2);


    return res;


}

int main()
{
    int a,b;
    cin>>a>>b;
    cout<<1ull*(nr(b)-nr(a-1));
    return 0;
}