// WA all region C second tour 15/16

# include <iostream>
# include <map>


using namespace std;

int32_t count_n(int32_t x) {
    int32_t cur_count = 0;
    while (x != 0) {
        x /= 10;
        cur_count++;
    }
    return cur_count;
}

void ans(int32_t &n, int32_t k, int32_t cur, int32_t &barrier, int32_t &count, map<int32_t, bool> &counted) {
    if (cur <= barrier && cur != 0 && !counted[cur]) {
        count++;
        counted[cur] = true;
    }
    if (k != n) {
        for (size_t i = cur % 10; i < 10; i++) {
            if (!(cur == 0 && i == 0)) {
                ans(n, k + 1, cur * 10 + i, barrier, count, counted);
            }
        }
    }
}

int main() {
    int32_t left, right;
    int32_t count, n;
    map<int32_t, bool> counted;
    cin >> left;
    cin >> right;
    n = count_n(right);
    ans(n, 0, 0, right, count, counted);
    cout << count;
    return 0;
}