#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <queue>
using namespace std;

long long d[10], p[10];

long long f(long long a) {
    if(a == 0) return 0;
    long long a1 = a, d1 = a*10, pw = 1;
    int i = 0;
    while(a1) {
        a1 /= 10;
        d1 /= 10;
        pw *= 10;
        i++;
    }
    pw /= 10;
    a1 = a - pw * d1;
    
    long long ans = 0;
    for(int dd = 0; dd < d1; ++dd) {
        ans += dd * p[i-1] / 2;
        ans += d[i-1];
    }
    ans += d1 * (a1+1) / 2;
    ans += f(a1);
    return ans;
}

long long ff(int a) {
    return a % 2 != 0 ? f(a+1) : f(a);
}

int main()
{
    p[0] = 1;
    d[0] = 0;   // ?
    for(int i = 1; i < 10; ++i) {
        p[i] = p[i-1] * 10;
        d[i] = p[i-1] * 25 + p[i-1] * 45 * (i-1) / 2;
    }
    
    //for(int i = 0; i < 10; ++i) {
    //    cout << p[i] << " " << d[i] << endl;
    //}
    
    
    //int a;
    //cin >> a;
    
    //for(int i = 0; i <= 150; ++i)
    //    cout << i << " " << ff(i) << endl;
    
    int a, b;
    cin >> a >> b;
    cout << ff(b) - ff(a-1) << endl;
    
    //cout << f(a) << endl;
    
    return 0;
}

//10 25
//100 475
//1000 7000
//10000 92500
//100000 1150000
//1000000 13750000
//10000000 160000000