#include <iostream>
#include <cstdio>

using namespace std;

long long F(int x) {
    long long ans = 0;
    long long total = 7000;

    int inainte = 1;
    long long sumcif = 0;

    while(inainte * 1000 <= x) {
        ans += total + sumcif * 500;

        int aux = inainte;
        sumcif = 0;

        while(aux) {
            sumcif += aux % 10;
            aux /= 10;
        }

        ++inainte;
    }

    for(int i = (inainte - 1) * 1000 + 1; i <= x; i += 2) {
        int aux = i;
        sumcif = 0;

        while(aux) {
            sumcif += aux % 10;
            aux /= 10;
        }

        ans += sumcif;
    }

    return ans;
}

int main() {
    #ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    #endif // ONLINE_JUDGE

    int A, B;

    cin >> A >> B;

    cout << F(B) - F(A - 1) << '\n';

    return 0;
}