#include <bits/stdc++.h>

#define sz(x)  (int)x.size()
#define bigint __int128
#define el '\n'
#define ll long long
#define int long long
#define ld long double
using namespace std;
const int N = 1e5 + 4, M = 1e5 + 10, mod = 998244353;
string l, r;
int dp[N][12][2][2];//[index, last, smaller  , allzeros ]
int add(int x, int y) {
    x %= mod;
    y %= mod;
    return (x + y + mod) % mod;
}
// zero
int solve(int i, int last, bool smaller, bool is_num, string &s) {
    if (i == s.size())
        return 1;

    int &ret = dp[i][last][smaller][is_num];
    if (~ret)
        return ret;
    ret = 0;
    for (int j = 0; j < 10; ++j) {
        if (last == j and (is_num))
            continue;
        if (!smaller and j > s[i] - '0') {
            continue;
        }
        ret = add(ret, solve(i + 1, j, smaller | (j < s[i] - '0'), (is_num |= (j != 0)), s));
    }
    return ret;
}

void acc() {
    cin >> l >> r;
    bool yes = true;
    for (int i = 1; i < l.size(); ++i) {
        if (l[i] == l[i - 1])
            yes = false;
    }
    memset(dp, -1, sizeof dp);
    long long rr = solve(0, 11, 0, 0, r);
    memset(dp, -1, sizeof dp);
    long long left = solve(0, 11, 0, 0, l);
    long long ans = add(rr, -left);
    ans = add(ans, yes);
    cout << ans << el;

}

signed main() {
    cout.tie(0);
    cin.tie(0);
    ios_base::sync_with_stdio(0);
    int t = 1;
    // cin >> t;
    while (t--)acc();
}