#include <iostream>
#include <limits>
#include <cmath>

bool isPrime(int n) {
    if (n <= 1) {
        return false;
    }

    for (int i = 2; i * i <= n; i++) {
        if (n % i == 0) {
            return false;
        }
    }

    return true;
}

int lowest_trivia_number (int I, int J) {
    double min_trivia = std::numeric_limits<double>::max();
    int res = 0;
    for (int i = I; i <= J; i++) {
        int sum_of_own_denominators = 1;
        for(int j = 2; j <= std::sqrt(i); j++){
            if(i % j == 0) {
                sum_of_own_denominators += j;
                if(j != i / j) {
                    sum_of_own_denominators += i / j;
                }
            }
        }

        double cur_trivia = sum_of_own_denominators/i;
        if (cur_trivia < min_trivia) {
            min_trivia = cur_trivia;
            res = i;
        }
    }
    return res;
}

int main() {
    int I, J;

    std::cin >> I >> J;
    if(I == 1) {
        std::cout << 1;
        return 0;
    }

    int largestPrime = -1;

    for (int num = J; num >= I; num--) {
        if (isPrime(num)) {
            largestPrime = num;
            break;
        }
    }

    if (largestPrime != -1) {
        std::cout << largestPrime << std::endl;
    } else {
        std::cout << lowest_trivia_number(I, J);
    }

    return 0;
}