#pragma GCC optimize("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("avx,avx2,fma")

#include <bits/stdc++.h>

#define ll long long
#define ld  double
using namespace std;

const int N = 2e5 + 5, lg = 19, mod = 998244353;

string s;

int dp[N][2][11][2];

int solve(int idx, bool less, int last, bool taken) {
    if(idx == (int) s.size()) return 1;

    int& ret = dp[idx][less][last][taken];
    if(ret != -1) return ret;

    ret = 0;
    for(int i = 0; i < 10; i++) {
        if(taken && last == i) continue;
        bool newLess = (i < (s[idx] - '0'));
        if(i > (s[idx] - '0') && less == 0) break;
        ret += solve(idx + 1, less | newLess, i, taken | (i > 0));
        if(ret >= mod) ret -= mod;
    }

    return ret;
}


int solve(string t) {
    s = t;
    memset(dp, -1, sizeof dp);
    return solve(0, 0, 0, 0);
}

bool tmam(string t) {
    for(int i = 0; i + 1 < (int) t.size(); i++) {
        if(t[i] == t[i + 1]) return 0;
    }
    return 1;
}


int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    string l, r;
    cin >> l >> r;
    int ans = solve(r) - solve(l) + tmam(l);

    if(ans < 0) ans += mod;
    if(ans >= mod) ans -= mod;

    cout << ans;

    return 0;
}