#include <bits/stdc++.h>
#define MOD 998244353
#define mod 1000000007
using namespace std;
const int maxn = 1e6+9;
bool isPrime(long long n)
{
    if (n <= 1) return false;
    for (long long i = 2; i <= (long long)sqrt(n); i++)
        if (!(n % i))
            return false;
    return true;
}
bool isSqrt(long long n)
{
    return sqrt(n) == long long(sqrt(n));
}
signed main()
{
	long long l,r,sum = 1;
    cin >> l >> r;
    for (int i = l; i <= r; i++) 
    {
        string s = to_string(i);
        long long cnt = 0;
        for (long long j = 0; j < (long long)s.length(); j++)
            cnt += s[j];
        if (isPrime(cnt) && isSqrt(i))
            sum *= i;
    }
    cout << sum % MOD;
	return 0;
}