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

long long mod = 998244353;
//入力が必ず-mod<a<modの時.
struct mint{
    long long v = 0;
    mint(){} mint(int a){v = a<0?a+mod:a;} mint(long long a){v = a<0?a+mod:a;}
    mint(unsigned long long a){v = a;}
    long long val(){return v;}
    void modu(){v %= mod;}
 
    mint repeat2mint(const long long a,long long b){
        mint ret = 1,p = a;
        while(b){
            if(b&1) ret *= p;
            p *= p; b >>= 1;
        }
        return ret;
    };
 
    mint &operator=(const mint &b) = default;
    mint operator-() const {return mint(0)-(*this);}
    mint operator+(const mint b){return mint(v)+=b;}
    mint operator-(const mint b){return mint(v)-=b;}
    mint operator*(const mint b){return mint(v)*=b;}
    mint operator/(const mint b){return mint(v)/=b;}
 
    mint operator+=(const mint b){
        v += b.v; if(v >= mod) v -= mod;
        return *this;
    }
    mint operator-=(const mint b){
        v -= b.v; if(v < 0) v += mod; 
        return *this;
    }   
    mint operator*=(const mint b){v = v*b.v%mod; return *this;}
    mint operator/=(mint b){
        if(b == 0) assert(false);
        int left = mod-2;
        while(left){if(left&1) *this *= b; b *= b; left >>= 1;}
        return *this;
    }
 
    mint operator++(int){*this += 1; return *this;}
    mint operator--(int){*this -= 1; return *this;}
    bool operator==(const mint b){return v == b.v;}
    bool operator!=(const mint b){return v != b.v;}
    bool operator>(const mint b){return v > b.v;}
    bool operator>=(const mint b){return v >= b.v;}
    bool operator<(const mint b){return v < b.v;}
    bool operator<=(const mint b){return v <= b.v;}
 
    mint pow(const long long x){return repeat2mint(v,x);}
    mint inv(){return mint(1)/v;}
};

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

    int N; cin >> N;
    vector<int> A(N);
    for(auto &a : A) cin >> a,a--;

    vector<int> start;
    for(int i=0; i<N; i++) if(A.at(i) == N-1) start.push_back(i);
    if(start.size() == 0){cout << "0\n"; return 0;}

    vector<pair<int,vector<int>>> B;
    for(auto s : start){
        vector<int> now = {N-1};
        for(int i=(s+1)%N; ; i=(i+1)%N){
            if(A.at(i) == N-1) break;
            now.push_back(A.at(i));
        }
        B.emplace_back(pair{s,now});
    }
    sort(B.begin(),B.end(),[&](auto &a,auto &b){return a.second.size()<b.second.size();});
    /*
    for(int i=B.size()-1; i<B.size(); i++){
        vector<int> now1 = B.at(i).second;
        for(int k=i-1; k>=0; k--){
            vector<int> now2 = B.at(k).second;
            while(now1.size() > now2.size()) now1.pop_back();
            if(now1 != now2){cout << "0\n"; return 0;}
        } 
    }
    */
    {
        auto [p,ign] = B.back();
        rotate(A.begin(),A.begin()+p,A.end());
        for(auto &[s,ign] : B) s = (s-p+N)%N; 
        start.clear();
        for(int i=0; i<N; i++) if(A.at(i) == N-1) start.push_back(i);
    }
    vector<vector<int>> check(N);
    for(auto s : start) for(int i=0; i<N; i++){
        int pos = (s+i)%N;
        if(A.at(pos) == N-1) continue;
        check.at(pos).push_back(i);
    }
    vector<vector<int>> sepa(N);
    for(int i=0; i<N; i++) sepa.at(A.at(i)).push_back(i);
    mint answer = 1;
    int hold = 0;
    vector<bool> already(N);
    for(int i=0; i<N-1; i++){
        hold++;
        if(sepa.at(i).size() == 0) continue;

        vector<int> count(N);
        for(auto g : sepa.at(i)) for(auto c : check.at(g)) count.at(c)++;
        int kouho = 0;
        vector<int> all;
        for(int k=0; k<N; k++){
            if(count.at(k) == sepa.at(i).size() && !already.at(k)){
                kouho++;
                if(kouho == 1) already.at(k) = true;
            }    
            if(count.at(k) > 0 && !already.at(k)) all.push_back(k);
        }    
        answer *= kouho; hold--;
        for(auto &p : all) answer *= hold,hold--,already.at(p) = true;
        if(hold < 0){cout << "0\n"; return 0;}
    }
    while(hold > 0) answer *= hold,hold--;
    answer *= N;
    cout << answer.v << "\n";
    return 0;
    vector<int> AA(N);
    iota(AA.begin(),AA.end(),0);

    int answer2 = 0;
    do{
        if(AA.at(0) != N-1) continue;
        vector<int> now(N);
        for(int i=0; i<N; i++) if(A.at(i) == N-1){
            for(int k=0; k<N; k++){
                int pos = (i+k)%N;
                now.at(pos) = max(now.at(pos),AA.at(k));
            }
        }
        if(now == A) answer2++;
    }while(next_permutation(AA.begin(),AA.end()));
    cout << answer2*N << endl;
}