#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define rep(i,n) for(int i=0;i<n;i++)
#define Pr pair<ll,ll>
#define Tp tuple<int,int,int>
#define all(v) v.begin(),v.end()
#define riano_ std::ios::sync_with_stdio(false);std::cin.tie(nullptr);typedef modint<mod> mint
using Graph = vector<vector<ll>>;

const ll mod = 998244353;
template<uint64_t mod>
struct modint{
    uint64_t val;
    constexpr modint(const int64_t val_=0) noexcept:val((val_%int64_t(mod)+int64_t(mod))%int64_t(mod)){}
    constexpr modint operator-() const noexcept{
        return modint(*this)=mod-val;
    }
    constexpr modint operator+(const modint rhs) const noexcept{
        return modint(*this)+=rhs;
    }
    constexpr modint operator-(const modint rhs) const noexcept{
        return modint(*this)-=rhs;
    }
    constexpr modint operator*(const modint rhs) const noexcept{
        return modint(*this)*=rhs;
    }
    constexpr modint operator/(const modint rhs) const noexcept{
        return modint(*this)/=rhs;
    }
    constexpr modint &operator+=(const modint rhs) noexcept{
        val+=rhs.val;
        val-=((val>=mod)?mod:0);
        return (*this);
    }
    constexpr modint &operator-=(const modint rhs) noexcept{
        val+=((val<rhs.val)?mod:0);
        val-=rhs.val;
        return (*this);
    }
    constexpr modint &operator*=(const modint rhs) noexcept{
        val=val*rhs.val%mod;
        return (*this);
    }
    constexpr modint &operator/=(modint rhs) noexcept{
        uint64_t ex=mod-2;
        modint now=1;
        while(ex){
            now*=((ex&1)?rhs:1);
            rhs*=rhs,ex>>=1;
        }
        return (*this)*=now;
    }
    constexpr bool operator==(const modint rhs) noexcept{
        return val==rhs.val;
    }
    constexpr bool operator!=(const modint rhs) noexcept{
        return val!=rhs.val;
    }
    friend constexpr ostream &operator<<(ostream& os,const modint x) noexcept{
        return os<<(x.val);
    }
    friend constexpr istream &operator>>(istream& is,modint& x) noexcept{
        uint64_t t;
        is>>t,x=t;
        return is;
    }
};


//累乗 aのb乗、正しmを法として求める
long long pw(long long a,long long b,long long m){
    if(b==0) return 1;
    else if(b%2==0){
        long long x = pw(a,b/2,m);
        return (x*x)%m;
    }
    else{
        long long x = pw(a,b-1,m);
        return (a*x)%m;
    }
}

// ll ranmod(ll l,ll r,ll d,ll N){
//     ll res = ((pw(10,r-l+1,mod)-1*d%mod)*pw(10,N-r,mod)%mod)*modinv(9,mod)%mod;
//     //cout << (pw(10,r-l+2,mod)-1*d%mod)*pw(10,N-r,mod)%mod << endl;
//     return res;
// }



// 最大公約数を求める
ll gcd(ll x,ll y){
    ll r=1;
    if(x<0) x *= -1;
    if(y<0) y *= -1;
    if(x<=y) swap(x,y);
    if(y==0) r=0;
    while(r>0){
        r=x%y;
        x=y;
        y=r;
    }
    return x;
}

//Combination2
//10^6くらいまで
//modはグローバルに定義しておく
long long modinv(long long a, long long m) {
    long long b = m, u = 1, v = 0;
    while (b) {
        long long t = a / b;
        a -= t * b; swap(a, b);
        u -= t * v; swap(u, v);
    }
    u %= m;
    if (u < 0) u += m;
    return u;
}
vector<ll> fact;
vector<ll> invf;
ll comb(ll n,ll k){
    if(n<0||k<0||k>n) return 0LL;
    else{
        ll a = fact[n]*invf[k]%mod;
        a = a*invf[n-k]%mod;
        return a;
    }
}
    
    

int main() {
    riano_; mint ans = 1;
    ll N; cin >> N;
    //main関数内に以下ペースト
    //N:max
    fact.assign(N+1,1LL);
    invf.assign(N+1,1LL);
    rep(i,N) fact[i+1] = fact[i]*(i+1)%mod;
    rep(i,N+1) invf[i] = modinv(fact[i],mod);
    ll p[N];
    ll ip[N];
    rep(i,N){
        cin >> p[i]; ip[p[i]] = i;
    }
    ll l = ip[0],r = ip[0];
    set<ll> in; in.insert(0);
    ll mx = 1;
    ll sp = 0;
    while(mx<N){
        ll s = ip[mx];
        if(s<l){
            for(int i=l-1;i>=s;i--){
                in.insert(p[i]);
            }
            sp += l-s-1;
            l = s;
        }
        else{
            for(int i=r+1;i<=s;i++){
                in.insert(p[i]);
            }
            sp += s-r-1;
            r = s;
        }
        ll pr = mx;
        while(in.count(mx)){
            mx++;
        }
        ans *= mint(comb(sp,mx-pr-1))*mint(fact[mx-pr-1]);
        //cout << mx << " " << ans << endl;
        sp -= mx-pr-1;
    }
    cout << ans << endl;
}