tj

//自行学习，不含注释
#include <bits/stdc++.h>

using namespace std;

long long first , last , sum = 0;

int main( ) {
    scanf("%lld %lld" , & first , & last);

    for (int i = first ; i <= last ; i++) {
        long long number = i;

        while (number) {
            sum += number % 10;
            number /= 10;
        }
    }

    printf("%lld\n" , sum);

    return 0;
}