#include #pragma GCC optmized(fast) #define forn(i,s,t) for(register int i=(s); i<=(t); ++i) #define forl(i,s,t) for(register i64 i=(s); i<=(t); ++i) #define form(i,s,t) for(register int i=(s); i>=(t); --i) #define rep(i,s,t) for(register int i=(s); i<(t); ++i) #define IT(u) for(register int i=G[u]; i; i=E[i].nxt) using namespace std; namespace FASTIO { const int SIZ = 1 << 26 | 1; char ibuf[SIZ], obuf[SIZ], *iS = ibuf, *iT = ibuf, *oS = obuf, *oT = obuf + SIZ - 1, qwq[60], qaq; #define gc() (iS == iT && (iT = (iS = ibuf) + fread(ibuf, 1, SIZ, stdin), iS == iT) ? EOF : *iS++) template inline void Rdn(T& A) { register bool fl = 0; register char ch = gc(); A = 0; while(!isdigit(ch)) fl = (ch == '-'), ch = gc(); while(isdigit(ch)) A = (A * 10) + (ch & 15), ch = gc(); fl && (A = -A); } inline void Rdn(char& c) {while((c = gc()) == ' ' || c == '\n' || c == '\r');} inline void Rdn(char* s) { while((*s = gc()) == ' ' || *s == '\n' || *s == '\r') ; if(*s == EOF) return ; while(*s != ' ' && *s != '\n' && *s != '\r' && *s != EOF) *(++s) = gc(); *s = 0; } template inline void Rdn(T& A, U& ...B) {Rdn(A), Rdn(B...);} inline void flush() {fwrite(obuf, 1, oS - obuf, stdout), oS = obuf;} inline void pc(char c) {*oS ++ = c; if(oS == oT) flush();} template inline void Wtn(T A) { if(!A) return pc('0'); if(A < 0) pc('-'), A = -A; while(A) qwq[++qaq] = A % 10 + '0', A /= 10; while(qaq) pc(qwq[qaq -- ]); } inline void Wtn(char A) {pc(A);} inline void Wtn(char *s) {while(*s) pc(*s), ++s;} inline void Wtn(const char *s) {while(*s) pc(*s), ++s;} template inline void Wtn(T A, U ...B) {Wtn(A), Wtn(B...);} #undef gc } const int Mod = 998244353; namespace Modint { struct Mint { int res; Mint() {} Mint(int _r) : res(_r) {} inline friend Mint operator + (const Mint& A, const Mint& B) { return Mint((A.res + B.res >= Mod) ? (A.res + B.res - Mod) : (A.res + B.res)); } inline friend Mint operator - (const Mint& A, const Mint& B) {return A + Mint(Mod - B.res); } inline friend Mint operator * (const Mint& A, const Mint& B) {return Mint(1ll * A.res * B.res % Mod); } inline friend Mint& operator += (Mint& A, const Mint& B) {return A = A + B; } inline friend Mint& operator -= (Mint& A, const Mint& B) {return A = A - B; } inline friend Mint& operator *= (Mint& A, const Mint& B) {return A = A * B; } inline friend Mint q_pow(Mint p, int k = Mod - 2) { Mint res(1); for (; k; k >>= 1, p *= p) (k & 1) && (res *= p, 0); return res; } } ; } using Modint :: Mint; using FASTIO :: Rdn; using FASTIO :: Wtn; using FASTIO :: flush; typedef long long i64; typedef double f64; typedef unsigned long long u64; typedef pair pii; typedef pair piu; const int N = 2e5 + 5; const i64 INF = 1e18; inline void init() {} int n, P[N], pos[N]; Mint fac[N]; inline void solve() { Rdn(n); forn (i, 1, n) Rdn(P[i]), pos[P[i]] = i; int l = min(pos[0], pos[1]), r = max(pos[0], pos[1]); fac[0] = Mint(1); forn (i, 1, n) fac[i] = fac[i - 1] * Mint(i); Mint res(1); int num = 2; rep (i, 2, n) if (l > pos[i] || pos[i] > r) { if (pos[i] < l) l = pos[i]; else r = pos[i]; num ++ ; } else { res *= Mint(r - l + 1 - num), num ++ ; } Wtn(res.res, '\n'); } int Trd; int main() { Trd = 1; while(Trd--) init(), solve(); flush(); return 0; }