import std;

void main () {
    int N = readln.chomp.to!int;
    string S = readln.chomp;

    solve(N, S);
}

void solve (int N, string S) {
    /*
       dp的に解く
       新しい区間を導入したとき、そこで切るか切らないかの2択
     */
    bool ok = false;
    foreach (c; S) if (c == '1') ok = true;
    if (!ok) {
        writeln(0);
        return;
    }

    const int MOD = 998244353;

    long ans = 1; // カットしないやつ

    // 右と左の0を削除
    foreach (i, c; S) if (c == '1') { S = S[i..$]; break; }
    foreach_reverse (i, c; S) if (c == '1') { S = S[0..i+1]; break; }

    int len = 0;
    int cur = 1;
    while (true) {
        if (cur == S.length) {
            break;
        }
        if (S[cur] == '1') {
            ans *= len+2;
            ans %= MOD;
            len = -1;
        }
        len++;
        cur++;
    }

    writeln(ans);
}

long modPow (long a, long x, ref const long MOD) {
    import std.exception : enforce;

    enforce(0 <= x, "x must satisfy 0 <= x");
    enforce(1 <= MOD, "MOD must satisfy 1 <= MOD");
    enforce(MOD <= int.max, "MOD must satisfy MOD*MOD <= long.max");

    // normalize
    a %= MOD; a += MOD; a %= MOD;

    long res = 1L;
    long base = a;
    while (0 < x) {
        if (0 < (x&1)) (res *= base) %= MOD;
        (base *= base) %= MOD;
        x >>= 1;
    }

    return res % MOD;
}

T modPow (T, X, Y) (T a, X x, ref const Y MOD) {
    import std.exception: enforce;

    enforce(0 <= x, "x must satisfy 0 <= x");
    enforce(1 <= MOD, "MOD must satisfy 1 <= MOD");

    // normalize
    a %= MOD; a += MOD; a %= MOD;

    T res = 1;
    T base = a;
    while (0 < x) {
        if (0 < (x&1)) (res *= base) %= MOD;
        (base *= base) %= MOD;
        x >>= 1;
    }

    return res % MOD;
}