#include <bits/stdc++.h>
#define endl '\n'
#define int long long
#define x first
#define y second
#define pb push_back
using namespace std;
typedef pair<int, int> PII;

const int maxn = 1e6 + 10, mod = 998244353;
string s, t;
int l, r, sz;
int ans[maxn], cnt[maxn], nxt[maxn];
int sans[maxn], scnt[maxn], snxt[maxn];
int ssans, sscnt, ssnxt;

typedef __int128 ull;
ull base = 131;
ull mod1 = 212370440130137957, mod2 = 1e9 + 7;
ull hs1[maxn], hs2[maxn], ht1[maxn], ht2[maxn];
ull pw1[maxn], pw2[maxn];

void init()
{
    pw1[0] = pw2[0] = 1;
    for (int i = 1; i < maxn; i++) pw1[i] = pw1[i - 1] * base % mod1;
    for (int i = 1; i < maxn; i++) pw2[i] = pw2[i - 1] * base % mod2;
}

bool check(int ls, int rs, int lt, int rt) {
    ull u1, u2, v1, v2;
    if (ls == 0) {
        u1 = hs1[rs], u2 = hs2[rs];
    } else {
        u1 = ( hs1[rs] + mod1 - hs1[ls - 1] * pw1[rs - ls + 1] % mod1 ) % mod1;
        u2 = ( hs2[rs] + mod2 - hs2[ls - 1] * pw2[rs - ls + 1] % mod2 ) % mod2;
    }
    if (lt == 0) {
        v1 = ht1[rt], v2 = ht2[rt];
    } else {
        v1 = ( ht1[rt] + mod1 - ht1[lt - 1] * pw1[rt - lt + 1] % mod1 ) % mod1;
        v2 = ( ht2[rt] + mod2 - ht2[lt - 1] * pw2[rt - lt + 1] % mod2 ) % mod2;
    }
    return ( (u1 == v1) && (u2 == v2) );
}

int fd(int x) {
    int l = 0, r = min( (int)s.size() - x, (int)t.size() ) + 1;
    while (l + 1 < r) {
        int mid = l + r >> 1;
        if ( check(x, x + mid - 1, 0, mid - 1) ) l = mid;
        else r = mid;
    }
    if ( l == min( (int)s.size() - x, (int)t.size() ) ) return l;
    if ( l == min( (int)s.size() - x, (int)t.size() ) - 1 ) return l + 1;
    int xx = x + l + 1;
    int ll = 0, rr = min( (int)s.size() - xx, (int)t.size() - l - 1 ) + 1;
    while (ll + 1 < rr) {
        int mid = ll + rr >> 1;
        if ( check(xx, xx + mid - 1, l + 1, l + mid) ) ll = mid;
        else rr = mid;
    }
    return l + ll + 1;
}

void solve() {
    cin >> s >> t;
    hs1[0] = (ull)s[0] % mod1;
    hs2[0] = (ull)s[0] % mod2;
    for (int i = 1; i < (int)s.size(); i++) {
        hs1[i] = (hs1[i - 1] * base + (ull)s[i]) % mod1;
        hs2[i] = (hs2[i - 1] * base + (ull)s[i]) % mod2;
    }
    ht1[0] = (ull)t[0] % mod1;
    ht2[0] = (ull)t[0] % mod2;
    for (int i = 1; i < (int)t.size(); i++) {
        ht1[i] = (ht1[i - 1] * base + (ull)t[i]) % mod1;
        ht2[i] = (ht2[i - 1] * base + (ull)t[i]) % mod2;
    }
    l = r = (int)s.size() - 1, sz = 1;
    ans[l] = 1, cnt[l] = 1, nxt[l] = 3;
    ans[l + 1] = 0, cnt[l + 1] = 0, nxt[l + 1] = 0;
    sans[l] = 1, scnt[l] = 1, snxt[l] = 3;
    sans[l + 1] = 0, scnt[l + 1] = 0, snxt[l + 1] = 0;
    ssans = 1, sscnt = 1, ssnxt = 3;
    for (int i = (int)s.size() - 2; i >= 0; i--) {
        l--, sz++;
        int tmp1 = (ssans + ssnxt) % mod;
        int tmp2 = sscnt;
        int tmp3 = (ssnxt + 2 * sscnt) % mod;
        ans[l] = tmp1;
        ssans = (ssans + tmp1) % mod;
        cnt[l] = tmp2;
        sscnt = (sscnt + tmp2) % mod;
        nxt[l] = tmp3;
        ssnxt = (ssnxt + tmp3) % mod;
        sans[l] = (sans[l + 1] + ans[l]) % mod;
        scnt[l] = (scnt[l + 1] + cnt[l]) % mod;
        snxt[l] = (snxt[l + 1] + nxt[l]) % mod;
        int far = fd(i);
        if ( sz != far ) {
            sz = far;
            r = l + sz - 1;
            ssans = (sans[l] + mod - sans[r + 1]) % mod;
            sscnt = (scnt[l] + mod - scnt[r + 1]) % mod;
            ssnxt = (snxt[l] + mod - snxt[r + 1]) % mod;
            r--, sz--;
        }
    }
    cout << ssans << endl;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    init();
    int t = 1;
    // cin >> t;
    while (t--) solve();
    return 0;
}