#include <bits/stdc++.h>

using namespace std;

int S[100000];
int total;

int main() {
    int a, b;

    for(int i = 1; i < 100000; ++i) {
        for(int j = i; j; j /= 10)
            S[i] += j % 10;
        if(i % 2 == 1)
            total += S[i];
    }

    cin >> a >> b;
    if(a % 2 == 0) ++a;

    long long ans = 0;
    for(int i = a; i <= b;) {
        if(i % 100000 == 1 && i + 100000 <= b) {
            ans += 1LL * S[i / 100000] * 50000;
            ans += total;
            i += 100000;
        } else {
            ans += S[i / 100000] + S[i % 100000];
            i += 2;
        }
    }
    cout << ans;

    return 0;
}