#include<iostream>
#include<atcoder/modint>
using namespace std;
using mint=atcoder::modint998244353;
int N;
int P[2<<17],inv[2<<17];
bool vis[2<<17];
main()
{
	cin>>N;
	for(int i=0;i<N;i++)
	{
		cin>>P[i];
		inv[P[i]]=i;
	}
	int pc=1;
	int l=inv[0],r=inv[0];
	int rest=0;
	mint ans=1;
	while(pc<N)
	{
		int id=inv[pc];
		while(id<l)
		{
			l--;
			rest++;
			vis[P[l]]=true;
		}
		while(r<id)
		{
			r++;
			rest++;
			vis[P[r]]=true;
		}
		pc++;
		rest--;
		while(pc<N&&vis[pc])
		{
			pc++;
			ans=ans*rest--;
		}
	}
	while(rest)ans*=rest--;
	cout<<ans.val()<<endl;
}