#include<bits/stdc++.h>
    #include <ext/pb_ds/tree_policy.hpp>
    #include <ext/pb_ds/assoc_container.hpp>

    #define ll long long
    #define endl '\n'
    using namespace std;
    using namespace __gnu_pbds;

    template<typename T>
    using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
    const int N = 1e5+7, P1 = 31, P2 = 37, mod= 998244353;
    // idx , last , smallor not , broke zeros
    ll add( ll a, ll b)
    {
        a = (a + mod) %mod;
        b = (b + mod) % mod;
        return (a+b)%mod;
    }
    int dp[N][10][2][2];
    string  s;
    int solve(int idx , int last , int small ,  int zeros)
    {
        if ( idx == s.size())
            return zeros;

        int &ret = dp[idx][last][small][zeros];
        if (~ret)
            return ret;
        ret =0;
        for (int i = 0; i < 10; ++i) {
            if ( !small && s[idx]-'0' >= i && i != last)
            {
                ret = add(ret , solve(idx+1 ,i, s[idx]-'0' > i,1));
            }
            else if ( i != last && small)
            {
                ret = add(ret , solve(idx+1 ,i, 1,1));
            }
        }
        if (!zeros)
        {
            ret = add( ret , solve(idx+1 ,0,1,0));
        }
        return ret;
    }
    void doWork() {
        string  l , r;
        cin >> l >> r;
        s = l;
        memset(dp,-1,sizeof dp);
        ll ansl = solve(0,0,0,0);
        int cnt = 1;
        for (int i = 1; i < l.size(); ++i) {
            if ( l[i] == l[i-1])
                cnt = 0;
        }
        ansl = add( ansl , -cnt);
        s = r;
        memset(dp,-1,sizeof dp);
        ll ansr = solve(0,0,0,0);
        cout << add( ansr  , -ansl) << endl;

    }


    int main() {
        ios::sync_with_stdio(false);
        cout.tie(nullptr);
        cin.tie(nullptr);
        int t = 1;
        while (t--) {
            doWork();
        }
        return 0;
    }