#include<bits/stdc++.h>
#define F(i,l,r) for(int i=(l),i##end=(r);i<=i##end;++i)
#define G(i,l,r) for(int i=(l),i##end=(r);i>=i##end;--i)
#define x first
#define y second
#define pii pair<int,int>
#define mp(x,y) make_pair(x,y)
#define ep emplace_back
using namespace std;
typedef long long ll;
constexpr int N=5e5,mod=998244353;
int n,a[N+9];
int L[N+9],R[N+9],stk[N+9],dp[N+9],pos[N+9];
int qpow(int x,int y)
{
	int res=1;
	for(;y;y>>=1,x=(ll)x*x%mod)if(y&1)res=(ll)res*x%mod;
	return res;
}
int main()
{
	ios::sync_with_stdio(false);cin.tie(0);
	cin>>n;
	F(i,1,n)cin>>a[i],pos[a[i]]=i;
	int top=0;
	F(i,1,n)
	{
		while(top&&a[stk[top]]<a[i])
			R[stk[top--]]=i;
		L[i]=stk[top];
		stk[++top]=i;
	}
	F(i,1,top)R[stk[i]]=n+1;
	dp[0]=1;
	F(cc,1,n)
	{
		int i=pos[cc];
		dp[cc]=dp[0];
		dp[0]=dp[0]*(qpow(2,(ll)(i-L[i])*(R[i]-i))-1)%mod;
		F(j,L[i]+1,i-1)
		{
			dp[0]=(dp[0]+(ll)dp[a[j]]*(qpow(2,(j-L[i])*(R[i]-i))-1)%mod*(qpow(2,(i-j)*(R[i]-i))-1))%mod;
			dp[a[j]]=((ll)dp[a[j]]*(qpow(2,(ll)(i-j)*(R[i]-i))-1))%mod;
		}
		F(j,i+1,R[i]-1)
		{
			dp[0]=(dp[0]+(ll)dp[a[j]]*(qpow(2,(R[i]-j)*(i-L[i]))-1)%mod*(qpow(2,(j-i)*(i-L[i]))-1))%mod;
			dp[a[j]]=((ll)dp[a[j]]*(qpow(2,(ll)(j-i)*(i-L[i]))-1))%mod;
		}
		F(j,1,cc-1)if(pos[j]<L[i]||pos[j]>R[i])dp[j]=(ll)dp[j]*(qpow(2,(i-L[i])*(R[i]-i))-1)%mod;
	}
	int ans=0;
	F(i,0,n)
	{
		ans+=dp[i];
		if(ans>=mod)ans-=mod;
	}
	cout<<ans<<'\n';
	return 0;
}