E

#include <iostream>
using namespace std;

long check(long k) {
    long s = 0;
    while (k) {
        s += k % 10;
        k /= 10;
    }
    return s;
}

int main() {
    long a, b;
    long n = 0;
    cin >> a >> b;
    for (long i = a; i <= b; i++) {
        if (check(i) % 2 != 0)
            n++;
    }
    cout << n;
    return 0;
}