#include<bits/stdc++.h>
using namespace std;
#define mod 998244353
#define ll long long int


int main(){
	int T=1;
	//cin>>T;
	assert(1 <= T && T <= 10);
	while(T--){
		int n,i;
		cin>>n;
		int a[n];
		int pos[n];
		for(i=0;i<n;i++){
			cin>>a[i];
			pos[a[i]]=i;
		}
		int l=pos[0];
		int r=pos[0];
		ll ans=1;
		for(i=1;i<n;i++){
			if(pos[i]<r&&pos[i]>l){
				ll z=(r-l+1)-i;
				ans=(ans*z)%mod;
			}
			else
			{
				l=min(l,pos[i]);
				r=max(r,pos[i]);
			}
		}
		cout<<ans<<"\n";



	}

	

}