#include <bits/stdc++.h>
using namespace std;
struct INIT{INIT(){ios::sync_with_stdio(false);cin.tie(0);}}init;
typedef long long LL;
vector<LL> prime;
struct eratosthenes{
    eratosthenes(){
        vector<bool> used(110001,true);
        for(int i = 2; i*i <= 110000; i++){
            if(used[i]){
                for(int j = i+i; j <= 110000; j+=i)
                    used[j]=false;
            }
        }
        for(int i = 2; i <= 110000; i++){
            if(used[i])prime.push_back(i);
        }
    }
}e;
int main() {
    LL L,H;
    cin >> L >> H;
    LL b=0;
    for(; prime[b]*prime[b] <= H; b++);
    b--;
    LL c=b;
    for(; prime[b]*prime[c] <= H; c++);
    c--;
    L=max(L,prime[b]*prime[c]);
    int sz=H-L+1;
    vector<pair<LL,LL>> res(sz,pair<LL,LL>(114514,0));
    for(int i = 0; i < sz; i++)
        res[i].second=L+i;
    for(auto& p : prime){
        LL d=(L+p-1)/p;
        d=d*p-L;
        for(int i = d;i < sz; i+=p)
            if(res[i].second!=p)
            res[i].first=min(res[i].first,p);
    }
    pair<LL,LL> ans;
    for(auto& it : res){
        if(it.first!=114514)ans=max(ans,it);
    }
    cout << ans.second << endl;
    return 0;
}