/*
     Hell, 'til I reach Hell, I ain't scared
     Mama checkin' in my bedroom, I ain't there
                                                */
    #include<bits/stdc++.h>
    #include <ext/pb_ds/assoc_container.hpp>
    #include <ext/pb_ds/tree_policy.hpp>
    using namespace __gnu_pbds;
    using namespace std;

    #define Major  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    #define TxtIO   freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
    #define read(a,n) for(int i = 0 ; i<n ; i++) cin>>a[i];
    #define write(a) for(auto x : a) cout<<x<<" ";
    #define int long long
    #define pb push_back
    #define all(a)  a.begin(),a.end()
    #define el "\n"

    typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

    const int inf=4e18;

    int dx[]={1,0,-1,0,1,1,-1,-1};
    int dy[]={0,1,0,-1,1,-1,1,-1};

    const int mod=998244353;
    const int MAX =2e5+7;

    //---------------------------Function----------------------------------//
    int dp[MAX][11][2][2];
    int add(int x,int y){
        return (x%mod + y%mod)%mod;
    }
    int solve(string &s,int idx,int last,bool less,bool started){
        if(idx==s.size())return 1;
        int &ret=dp[idx][last][less][started];
        if(~ret)return ret;
        ret=0;
        for(int i=0;i<10;i++){
            if(!less&&i>(s[idx]-'0'))break;
            if(i==last && started)continue;
            int lesser=(i<(s[idx]-'0'));
            ret=add(ret,solve(s,idx+1,i,lesser|less,started|(i>0)));
            if(ret>=mod)ret-=mod;
        }
        return ret;
    }
    void TestCake(){
        string l,r;cin>>l>>r;
        memset(dp,-1,sizeof dp);
        int ansl=solve(l,0,0,0,0);
        memset(dp,-1,sizeof dp);
        int ansr=solve(r,0,0,0,0);
        int ans=add(-ansl,ansr);
        int ok=0;
        for(int i=1;i<l.size();i++){
            if(l[i]==l[i-1])ok=1;
        }
        ans=add(ans,!ok);
        while(ans<0)ans+=mod;
        ans%=mod;
       
        cout<<ans<<el;
    }
    //------------------------------Main---------------------------//
    signed main(){
        Major
        int T = 1;
//        cin >> T;
        while(T--){
            TestCake();
        //       cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
        }
        return 0;
    }