#include <bits/stdc++.h>

using namespace std;
int n, m;
int cnt;
bool check(int x) {
    while (x) {
        int r = x % 10;
        if (r % 2 == 0) return false;
        x /= 10;
    }
    return true;
}
int main() {
    cin >> n >> m;
    for (int i = n; i <= m; i++)
        if (check(i)) cnt++;

    printf("%d\n", cnt);
    return 0;
}