#include <bits/stdc++.h>
using namespace std;
const int maxn = 3000000 * 2 + 5;
const int P = 998244353;
typedef long long LL;
int n;
int sz, tot, last;
int cnt[maxn], ch[maxn][11], len[maxn], fail[maxn],pos[maxn];
int s[maxn];
int node(int l,int p) {
    sz++;
    memset(ch[sz], 0, sizeof(ch[sz]));
    len[sz] = l;
    fail[sz] = cnt[sz] = 0;
    pos[sz] = p;
    return sz;
}
void clear() {  // 初始化
    sz = -1; last = 0;
    s[tot = 0] = 10;
    node(0,0); node(-1,0);
    fail[0] = 1;
}
int getfail(int x) {
    while (s[tot - len[x] - 1] != s[tot]) x = fail[x];
    return x;
}
void insert(int c,int p) {
    s[++tot] = c;
    int now = getfail(last);
    if (!ch[now][c]) {
        int x = node(len[now] + 2,p);
        fail[x] = ch[getfail(fail[now])][c];
        ch[now][c] = x;
    }
    last = ch[now][c];
    if(p>n)cnt[last]++;
}
LL Ans;
void solve() {
    long long ans = 0;
    for (int i = sz; i >= 0; i--) {
        cnt[fail[i]] += cnt[i];
    }
    for (int i = 2; i <= sz; i++) {
        if (len[i] > n)continue;
        Ans += 1ll * len[i] * cnt[i] % P * cnt[i] % P;
        Ans %= P;
    }
}

string b;
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    clear();
    cin >> n;
    cin >> b;
    for (int i = 0; i < n; i++)insert(b[i] - '0',i+1);
    for (int i = 0; i < n; i++)insert(b[i] - '0',i+n+1);
    solve();
    cout << Ans << '\n';
    return 0;
}