#include <bits/stdc++.h>
#define x first
#define y second
#define int long long
using namespace std;
typedef pair<int,int> PII;
typedef unsigned long long ULL;
const int N = 5e3+10,INF=1e16,mod = 998244353;
const ULL MOD =(1ULL << 61) -1,P=1002;
int get(int x)
{
    return (x%mod+mod)%mod;
}
ULL mul(ULL a,ULL b)
{
    auto ans = __uint128_t(a)*b;
    ans =(ans>>61)+(ans&MOD);
    if(ans>=MOD)ans-=MOD;
    return ans;
}
void solve()
{
    string S,T;
    cin>>S>>T;
    int n = S.size(),m=T.size();
    vector<ULL>hs(n+2,0),ht(m+1,0),p(n+m+1,0);
    S='0'+S,T='0'+T;
    p[0]=1;
    for(int i=1;i<=n+m;i++)p[i]=mul(p[i-1],P);
    for(int i=1;i<=n;i++)
    {
        hs[i]=mul(hs[i-1],P)+S[i];
        if(hs[i]>=MOD)hs[i]-=MOD;
    }
    for(int i=1;i<=m;i++)
    {
        ht[i]=mul(ht[i-1],P)+T[i];
        if(ht[i]>=MOD)ht[i]-=MOD;
    }
    vector<array<int,3>>dp(n+5,{0,0,0}),s(n+5,{0,0,0});
    dp[0][0]=1;
    for(int i=1;i<=n;i++)
    {
        int L1=i-1,L2=0;
        int l=0,r=min(n-i+1,m);
        while(l<r)
        {
            int mid = l+r+1>>1;
            ULL t1 = hs[L1+mid]+MOD-mul(hs[L1],p[mid]);
            if(t1>=MOD)t1-=MOD;
            ULL t2 = ht[L2+mid]+MOD-mul(ht[L2],p[mid]);
            if(t2>=MOD)t2-=MOD;
            if(t1==t2)  l=mid;
            else    r=mid-1;
        }
        if(L1+l!=n&&L2+l!=m)
        {
            L1+=l+1,L2+=l+1;
            l=0,r=min(n-L1,m-L2);
            while(l<r)
            {
                int mid = l+r+1>>1;
                ULL t1 = hs[L1+mid]+MOD-mul(hs[L1],p[mid]);
                if(t1>=MOD)t1-=MOD;
                ULL t2 = ht[L2+mid]+MOD-mul(ht[L2],p[mid]);
                if(t2>=MOD)t2-=MOD;
                if(t1==t2)  l=mid;
                else    r=mid-1;            
            }
        }
        L1+=l+1,L2+=l+1;
        s[i][2]+=dp[i-1][2]+2*dp[i-1][1]+dp[i-1][0];
        s[i][1]+=dp[i-1][1]+dp[i-1][0];
        s[i][0]+=dp[i-1][0];
        s[L1][2]-=dp[i-1][2]+2*dp[i-1][1]+dp[i-1][0];
        s[L1][1]-=dp[i-1][1]+dp[i-1][0];
        s[L1][0]-=dp[i-1][0];
        s[i][0]=get(s[i][0]),s[i][1]=get(s[i][1]),s[i][2]=get(s[i][2]);
        if(i>1)
        {
            dp[i][0]=(dp[i-1][0]+s[i][0])%mod;
            dp[i][1]=(dp[i-1][1]+s[i][1])%mod;
            dp[i][2]=(dp[i-1][2]+s[i][2])%mod;
        }
        else    dp[i][0]=dp[i][1]=dp[i][2]=1;
    }
    cout<<dp[n][2]<<"\n";
}

signed main()
{
    int T=1;
    cin.tie(0)->sync_with_stdio(false);
    //cin>>T;
    //init();
    while(T--)
    {
        solve();
    }
}