#include <bits/stdc++.h>
using namespace std;

const int MOD = 998244353;

int add(int a, int b) {
    return a + b >= MOD ? a + b - MOD : a + b;
}

int sub(int a, int b) {
    return a >= b ? a - b : a + MOD - b;
}

int mul(int a, int b) {
    return (1ll * a * b) % MOD;
}

int pw(int x, int n) {
    int res = 1;
    while (n) {
        if (n % 2 == 0) {
            x = mul(x, x);
            n /= 2;
        } else {
            res = mul(res, x);
            --n;
        }
    }
    return res;
}

const int G = 3;

void fft(vector<int>& a, bool inv = false) {
    int n = a.size();
    int k = 0;
    while ((1 << k) < n) ++k;
    static vector<int> rev, power = {0, 1};
    rev.resize(n);
    rev[0] = 0;
    for (int i = 1; i < n; ++i) {
        rev[i] = rev[i / 2] / 2 + ((i & 1) << (k - 1));
        if (i < rev[i]) {
            swap(a[i], a[rev[i]]);
        }
    }
    for (int l = 1; l < n; l *= 2) {
        if ((int)power.size() == l) {
            power.resize(2 * l);
            int w = pw(G, (MOD - 1) / 2 / l);
            for (int i = l; i < 2 * l; ++i) {
                power[i] = power[i / 2];
                if (i & 1) power[i] = mul(power[i], w);
            }
        }
        for (int i = 0; i < n; i += 2 * l) {
            for (int j = 0; j < l; ++j) {
                int x = a[i + j], y = mul(a[i + j + l], power[j + l]);
                a[i + j] = add(x, y);
                a[i + j + l] = sub(x, y);
            }
        }
    }
    if (inv) {
        reverse(a.begin() + 1, a.end());
        int anti = pw(n, MOD - 2);
        for (int i = 0; i < n; ++i) {
            a[i] = mul(a[i], anti);
        }
    }
}

vector<int> operator*(vector<int> a, vector<int> b) {
    int sz = a.size() + b.size() - 1;
    int k = 0;
    while ((1 << k) < sz) ++k;
    a.resize(1 << k);
    b.resize(1 << k);
    fft(a); fft(b);
    for (int i = 0; i < (1 << k); ++i) {
        a[i] = mul(a[i], b[i]);
    }
    fft(a, true);
    a.resize(sz);
    return a;
}

const int MAXN = 2e5 + 100;
int used[MAXN];

int dp[MAXN], fact[MAXN];

void go(int l, int r) {
    if (r - l == 1) {
        if (!used[l]) dp[l] = 0;
        return;
    }
    int m = (l + r) / 2;
    go(l, m);
    vector<int> dpl(dp + l, dp + m);
    vector<int> upd(fact, fact + r - l);
    vector<int> dpr = dpl * upd;
    for (int i = m; i < r; ++i) {
        dp[i] = sub(dp[i], dpr[i - l]);
    }
    go(m, r);
}

void solve_() {
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < m; ++i) {
        int x;
        cin >> x;
        used[x] = 1;
    }
    for (int i = 1; i < 2 * n; i += 2) {
        if (!used[2 * n - i]) {
            used[i] = 0;
        }
    }
    used[0] = used[2 * n] = 1;
    dp[0] = sub(0, 1);
    go(0, 2 * n + 1);
    cout << dp[2 * n] << "\n";
}

/// #define MULTITEST

main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    fact[0] = 1;
    for (int i = 1; i < MAXN; ++i) {
        fact[i] = mul(fact[i - 1], i);
    }

    int tst = 1;
#ifdef MULTITEST
    cin >> tst;
#endif // MULTITEST
    while (tst--) {
        solve_();
    }
    return 0;
}