#include <cstdio>
const int M = 200005;
const int MOD = 998244353;
int read()
{
	int x=0,f=1;char c;
	while((c=getchar())<'0' || c>'9') {if(c=='-') f=-1;}
	while(c>='0' && c<='9') {x=(x<<3)+(x<<1)+(c^48);c=getchar();}
	return x*f;
}
int n,a[M],b[M],dp[M],sum[M];
signed main()
{
	n=read();dp[0]=1;
	int j=0,k=1,cnt=0;
	for(int i=1;i<=n;i++)
	{
		a[i]=read();
		dp[i]=dp[i-1];//do nothing
		if(a[i]==a[i-1]) j=i-1;
		if(i>2 && a[i]!=a[i-1] && a[i-1]!=a[i-2])
			dp[i]=(dp[i]+dp[i-2])%MOD;
		//
		if(b[a[i]]==0) cnt++;
		b[a[i]]++;
		while(k<i-2 && cnt>=3)
		{
			b[a[k]]--;
			if(b[a[k]]==0) cnt--;
			k++;
		}
		//
		if(j<k) dp[i]+=sum[k-1]-sum[j];
		dp[i]=(dp[i]%MOD+MOD)%MOD;
		sum[i]=(sum[i-1]+dp[i])%MOD;
	}
	printf("%d\n",dp[n]);
}