#ifndef LOCAL
#define FAST_IO
#endif

// ============
#include <bits/stdc++.h>
#define OVERRIDE(a, b, c, d, ...) d
#define REP2(i, n) for (i32 i = 0; i < (i32)(n); ++i)
#define REP3(i, m, n) for (i32 i = (i32)(m); i < (i32)(n); ++i)
#define REP(...) OVERRIDE(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define PER2(i, n) for (i32 i = (i32)(n)-1; i >= 0; --i)
#define PER3(i, m, n) for (i32 i = (i32)(n)-1; i >= (i32)(m); --i)
#define PER(...) OVERRIDE(__VA_ARGS__, PER3, PER2)(__VA_ARGS__)
#define ALL(x) begin(x), end(x)
#define LEN(x) (i32)(x.size())
using namespace std;
using u32 = unsigned int;
using u64 = unsigned long long;
using i32 = signed int;
using i64 = signed long long;
using f64 = double;
using f80 = long double;
using pi = pair<i32, i32>;
using pl = pair<i64, i64>;
template <typename T>
using V = vector<T>;
template <typename T>
using VV = V<V<T>>;
template <typename T>
using VVV = V<V<V<T>>>;
template <typename T>
using VVVV = V<V<V<V<T>>>>;
template <typename T>
using PQR = priority_queue<T, V<T>, greater<T>>;
template <typename T>
bool chmin(T &x, const T &y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}
template <typename T>
bool chmax(T &x, const T &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}
template <typename T>
i32 lob(const V<T> &arr, const T &v) {
    return (i32)(lower_bound(ALL(arr), v) - arr.begin());
}
template <typename T>
i32 upb(const V<T> &arr, const T &v) {
    return (i32)(upper_bound(ALL(arr), v) - arr.begin());
}
template <typename T>
V<i32> argsort(const V<T> &arr) {
    V<i32> ret(arr.size());
    iota(ALL(ret), 0);
    sort(ALL(ret), [&](i32 i, i32 j) -> bool {
        if (arr[i] == arr[j]) {
            return i < j;
        } else {
            return arr[i] < arr[j];
        }
    });
    return ret;
}
#ifdef INT128
using u128 = __uint128_t;
using i128 = __int128_t;
#endif
[[maybe_unused]] constexpr i32 INF = 1000000100;
[[maybe_unused]] constexpr i64 INF64 = 3000000000000000100;
struct SetUpIO {
    SetUpIO() {
#ifdef FAST_IO
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
#endif
        cout << fixed << setprecision(15);
    }
} set_up_io;
void scan(char &x) { cin >> x; }
void scan(u32 &x) { cin >> x; }
void scan(u64 &x) { cin >> x; }
void scan(i32 &x) { cin >> x; }
void scan(i64 &x) { cin >> x; }
void scan(string &x) { cin >> x; }
template <typename T>
void scan(V<T> &x) {
    for (T &ele : x) {
        scan(ele);
    }
}
void read() {}
template <typename Head, typename... Tail>
void read(Head &head, Tail &...tail) {
    scan(head);
    read(tail...);
}
#define CHAR(...)     \
    char __VA_ARGS__; \
    read(__VA_ARGS__);
#define U32(...)     \
    u32 __VA_ARGS__; \
    read(__VA_ARGS__);
#define U64(...)     \
    u64 __VA_ARGS__; \
    read(__VA_ARGS__);
#define I32(...)     \
    i32 __VA_ARGS__; \
    read(__VA_ARGS__);
#define I64(...)     \
    i64 __VA_ARGS__; \
    read(__VA_ARGS__);
#define STR(...)        \
    string __VA_ARGS__; \
    read(__VA_ARGS__);
#define VEC(type, name, size) \
    V<type> name(size);       \
    read(name);
#define VVEC(type, name, size1, size2)    \
    VV<type> name(size1, V<type>(size2)); \
    read(name);
// ============

#ifdef DEBUGF
#else
#define DBG(...) (void)0
#endif

#include <atcoder/convolution>

using M = atcoder::modint998244353;

void solve() {
    I32(n);
    VEC(i32, a, n);
    reverse(ALL(a));
    i32 s = a[n - 1] + 1;
    V<i32> cnt(s, 0);
    REP(i, n) {
        ++cnt[a[i]];
    }
    V<M> cf(s);
    REP(i, s) {
        cf[i] = M(2).pow(cnt[i]) - M(1);
    }
    DBG(cf);
    V<M> fact(s), invfact(s);
    fact[0] = M(1);
    REP(i, 1, s) {
        fact[i] = fact[i - 1] * M(i);
    }
    invfact[s - 1] = fact[s - 1].inv();
    PER(i, s - 1) {
        invfact[i] = invfact[i + 1] * M(i + 1);
    }
    DBG(fact, invfact);
    V<M> dp(s);
    auto rec = [&](auto rec, i32 l, i32 r) -> void {
        if (r - l == 1) {
            dp[l] += cf[l];
            return;
        }
        i32 mid = (l + r) / 2;
        rec(rec, l, mid);
        V<M> arr1(dp.begin() + l, dp.begin() + mid);
        REP(i, l, mid) {
            arr1[i - l] *= invfact[i];            
        }
        V<M> arr2(invfact.begin(), invfact.begin() + (r - l));
        V<M> conv = atcoder::convolution(arr1, arr2);
        REP(i, mid, r) {
            dp[i] += conv[i - l] * fact[i] * cf[i];
        }
        rec(rec, mid, r);
    };
    rec(rec, 0, s);
    DBG(dp);
    M ans = accumulate(ALL(dp), M());
    cout << ans.val() << '\n';
}

int main() {
    i32 t = 1;
    // cin >> t;
    while (t--) {
        solve();
    }
}