#include<bits/stdc++.h>
using namespace std;
#define ll unsigned long long 
ll su(ll a){
	if(a==1) return 0;
	for(ll i=2;i<=sqrt(a);i++){
		if(a%i==0){
			return 0;
		}
	}
	return 1;
}
int main(){
	ll a[1141511],num=0,sum=1;
	for(ll i=1;i*i<=1e12;i++){
		ll qwq=i*i;
		while(qwq){
			num+=qwq%10;
			qwq/=10;
		}
		if(su(num)==1){
			a[++sum]=i*i;
		}
		num=0;
	}
	ll kkksc03,sb,ans=1;
	cin>>kkksc03>>sb;
	for(ll i=1;i<=sum;i++){
		if(a[i]>=kkksc03&&a[i]<=sb) ans=ans*a[i]%998244353;
		if(a[i]>sb) break;
	}
	if(ans>1){
		cout<<ans;
	}else{
		cout<<0;
	}
	return 0;
}