//Code by dXqwq, who is still searching painless suicide.
#include<bits/stdc++.h>
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
using namespace std;
inline int read(){
   int s=0,w=1;
   char ch=getchar();
   while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
   while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
   return s*w;
}
int a[503];
bool b[503];
int nxt[503];
const int p=998244353;
int f[503][503];
signed main()
{
	int n=read();
	for(int i=1; i<=n; ++i) b[a[i]=read()]=1;
	sort(a+1,a+n+1);
	n=unique(a+1,a+n+1)-a-1;
	for(int i=a[n]; i>=0; --i)
		if(b[i]) nxt[i]=i;
		else nxt[i]=nxt[i+1];
	sort(a+1,a+n+1);
	int ans=1;
	for(int t=1; t<=a[n]; ++t) //first=t
	{
		memset(f,0,sizeof(f));
		if(b[t]) f[t][t]=1;
		else f[t+1][t]=1;
		for(int i=t; i<a[n]; ++i)
		{
			for(int j=t; j<=i; ++j)
			{
				if(nxt[i]==nxt[i+1]&&i!=j)
				{
					if((i+1)-j<t)
						f[i+1][j]=(f[i+1][j]+f[i][j])%p;
				}
				else
				{
					if((i+1)-j<t)
						f[i+1][j]=(f[i+1][j]+f[i][j])%p;
					f[i+1][i+1]=(f[i+1][i+1]+f[i][j])%p;
				}
			}
		}
		for(int i=t; i<=a[n]; ++i)
			ans=(ans+f[a[n]][i])%p;
	}
	printf("%d\n",ans);
	return 0;
}