#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<string>
#include<vector>
#include<map>
#include<list>
#include<stack>
#include<queue>
#include<climits> //INT_MIN/MAX


using namespace std;

#define FOR(i,s,e) for(int (i)=(s);(i)<(e);(i)++)
#define FORR(i,s,e) for(int (i)=(s);(i)>(e);(i)--)
#define MOD 1000000007
#define llong long long



int main()
{
    cin.tie(0);
    ios_base::sync_with_stdio(false);

    llong int L, H;
    cin >> L >> H;

    int n = sqrt(H);
    vector<int> prime;
    vector<bool> a(n + 1);

    for (int s = 2; s <= n; s++) {
        if (a[s] == false) {
            for (long j = s*s; j <= n; j += s) {
                a[j] = true;
            }
            prime.push_back(s);
        }
    }



    FORR(i, prime.size() - 1, -1) {
        if (prime[i] * prime[i] <= H)
            for (long long int j = H; j >= L; j--) {
                if (j%prime[i] == 0) {
                    if (i == 0) { //素因数が最小の素数の場合 -> 2
                        cout << j << endl;
                        return 0;
                    }
                    for (int p = i - 1; p >= 0; p--) {
                        if (j%prime[p] == 0) {
                            break;
                        }
                        if (p == 0 && j%prime[p] != 0) {
                            cout << j << endl;
                            return 0;
                        }
                    }
                }

            }
    }

    return 0;
}