#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<long long> vi;
typedef vector<vi> vvi;
int MOD = 998244353;
vvi dp;

ll qexp(ll b, ll e) {
    ll ans = 1;
    for(; e > 0; e >>= 1, b = b * b % MOD) {
        if(e & 1) ans = ans * b % MOD;
    }
    return ans;
}

ll solve(string& s, int idx, char last) {
    ll ans = 0;
    if(idx >= (int) s.length()) return 1;
    if(last != '0' && s[idx] != '0') {
        ans = (ans + (qexp(9, s.length() - idx) - 1 + MOD) % MOD * qexp(8, MOD - 2) % MOD) % MOD;
        if(last != '9' + 1) ans = (ans - 1 + MOD) %MOD;
    }
    // cout << idx << " " << ans << "\n";
    for(int i = '1'; i < s[idx]; i++) {
        if(last == i) continue;
        ans = (ans + qexp(9, s.length() - idx - 1)) % MOD;
    }
    if(last != s[idx]) ans = (ans + solve(s, idx + 1,( s[idx] == '0' && last == '9' + 1 )? '9' + 1 : s[idx])) % MOD;
    // cout << s << " " << idx << " " << last << " " << ans << "\n";
    return ans;
}
ll solve_everule(string &s){
    int n = s.size();
    ll ans = 0;
    bool is_valid = 1;
    for(int i=0;i+1<n;i++){
        if(i > 0 && s[i] == s[i-1]){
            is_valid = 0;
            break;
        }
        ans += qexp(9, n - i - 2) * (s[i+1] - '0' - (s[i] < s[i+1]));
    }
    is_valid &= (s[n-1] != s[n-2]);
    ans += (s[0] - '1') * qexp(9, n - 1);
    for(int k=1;k<n;k++){
        ans += qexp(9, n - k);
    }
    ans += is_valid;
    ans %= MOD;
    return ans;
}
void solve() {
    string L, U; cin >> L >> U;
    ll ans = 1;
    int i = 0;
    for(; i < (int) L.length() - 1 && L[i] == '0'; i++) {}
    for(;i < (int) L.length() - 1; i++) {
        if(L[i] == L[i + 1]) {
            ans = 0;
            break;
        }
    }
    ans = (ans + solve_everule(U)) % MOD;
    // cout << ans << "\n";
    ans = (ans - solve_everule(L) + MOD) % MOD;
    cout << ans << "\n";
}
int main() {
    ios_base::sync_with_stdio(); cin.tie(0);
    int T = 1;
    //cin >> T;
    while(T--) {
        solve();
    }
}