# include "bits/stdc++.h" using namespace std; using LL = long long; using ULL = unsigned long long; const double PI = acos(-1); templateconstexpr T INF() { return ::std::numeric_limits::max(); } templateconstexpr T HINF() { return INF() / 2; } template T_char TL(T_char cX) { return tolower(cX); }; template T_char TU(T_char cX) { return toupper(cX); }; const int vy[] = { -1, -1, -1, 0, 1, 1, 1, 0 }, vx[] = { -1, 0, 1, 1, 1, 0, -1, -1 }; const int dx[4] = { -1,0,1,0 }, dy[4] = { 0,-1,0,1 }; int popcnt(unsigned long long n) { int cnt = 0; for (int i = 0; i < 64; i++)if ((n >> i) & 1)cnt++; return cnt; } int d_sum(LL n) { int ret = 0; while (n > 0) { ret += n % 10; n /= 10; }return ret; } int d_cnt(LL n) { int ret = 0; while (n > 0) { ret++; n /= 10; }return ret; } LL gcd(LL a, LL b) { if (b == 0)return a; return gcd(b, a%b); }; LL lcm(LL a, LL b) { LL g = gcd(a, b); return a / g*b; }; # define ALL(qpqpq) (qpqpq).begin(),(qpqpq).end() # define UNIQUE(wpwpw) (wpwpw).erase(unique(ALL((wpwpw))),(wpwpw).end()) # define LOWER(epepe) transform(ALL((epepe)),(epepe).begin(),TL) # define UPPER(rprpr) transform(ALL((rprpr)),(rprpr).begin(),TU) # define FOR(i,tptpt,ypypy) for(LL i=(tptpt);i<(ypypy);i++) # define REP(i,upupu) FOR(i,0,upupu) # define INIT std::ios::sync_with_stdio(false);std::cin.tie(0) # pragma warning(disable:4996) std::vector prime; void MakePrime(int n) { prime.emplace_back(2); for (int i = 3; i < n; i += 2) { bool a = false; for (int j = 3; j <= std::sqrt(i); j += 2) { if (i%j == 0) { a = true; } } if (a == false) { prime.emplace_back(i); } } } LL l, h; int main() { cin >> l >> h; MakePrime(101010); for (int i = prime.size() - 1; i >= 0; i--) { if (1LL * prime[i] * prime[i] <= h) { for (LL a = h / prime[i] * prime[i]; a >= max(l, 1LL * prime[i] * prime[i]); a -= prime[i]) { REP(x, i) { if (a%prime[x] == 0)break; if (x == i - 1) { cout << a << endl; return 0; } } } } } cout << h - (h % 2) << endl; }