#include <algorithm>
#include <bitset>
#include <cassert>
#include <complex>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <typeinfo>
#include <utility>
#include <vector>
#include <array>
#include <chrono>
#include <random>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <valarray>
#define INIT std::ios::sync_with_stdio(false);std::cin.tie(0);
#define VAR(type, ...)type __VA_ARGS__;Scan(__VA_ARGS__);
template<typename T> void Scan(T& t) { std::cin >> t; }
template<typename First, typename...Rest>void Scan(First& first, Rest&...rest) { std::cin >> first; Scan(rest...); }
#define OUT(d) std::cout<<d;
#define FOUT(n, d) std::cout<<std::fixed<<std::setprecision(n)<<d;
#define SOUT(n, c, d) std::cout<<std::setw(n)<<std::setfill(c)<<d;
#define SP std::cout<<" ";
#define TAB std::cout<<"\t";
#define BR std::cout<<"\n";
#define ENDL std::cout<<std::endl;
#define FLUSH std::cout<<std::flush;
#define VEC(type, c, n) std::vector<type> c(n);for(auto& i:c)std::cin>>i;
#define MAT(type, c, m, n) std::vector<std::vector<type>> c(m, std::vector<type>(n));for(auto& r:c)for(auto& i:r)std::cin>>i;
#define ALL(a) (a).begin(),(a).end()
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define RFOR(i, a, b) for(int i=(b)-1;i>=(a);--i)
#define REP(i, n) for(int i=0;i<int(n);++i)
#define RREP(i, n) for(int i=(n)-1;i>=0;--i)
#define FORLL(i, a, b) for(ll i=ll(a);i<ll(b);++i)
#define RFORLL(i, a, b) for(ll i=ll(b)-1;i>=ll(a);--i)
#define REPLL(i, n) for(ll i=0;i<ll(n);++i)
#define RREPLL(i, n) for(ll i=ll(n)-1;i>=0;--i)
#define PAIR std::pair<int, int>
#define PAIRLL std::pair<ll, ll>
#define IN(a, x, b) (a<=x && x<b)
#define SHOW(d) {std::cerr << #d << "\t:" << d << "\t";}
#define SHOWVECTOR(v) {std::cerr << #v << "\t:";for(const auto& i : v){std::cerr << i << " ";}std::cerr << "\n";}
#define SHOWVECTOR2(v) {std::cerr << #v << "\t:\n";for(const auto& i : v){for(const auto& j : i){std::cerr << j << " ";}std::cerr << "\n";}}
#define SHOWPAIRVECTOR2(v) {std::cerr << #v << "\t:\n";for(const auto& i : v){for(const auto& j : i){std::cerr<<'('<<j.first<<", "<<j.second<<") ";}std::cerr << "\n";}}
#define SHOWPAIRVECTOR(v) {for(const auto& i:v){std::cerr<<'('<<i.first<<", "<<i.second<<") ";}std::cout<<"\n";}
#define CHECKTIME(state) {auto start=std::chrono::system_clock::now();state();auto end=std::chrono::system_clock::now();auto res=std::chrono::duration_cast<std::chrono::nanoseconds>(end-start).count();std::cerr<<"[Time:"<<res<<"ns  ("<<res/(1.0e9)<<"s)]\n";}
#define SHOWQUEUE(a) {std::queue<decltype(a.front())> tmp(a);std::cerr << #a << "\t:";for(int i=0; i<static_cast<int>(a.size()); ++i){std::cerr << tmp.front() << "\n";tmp.pop();}std::cerr << "\n";}
#define CHMAX(a, b) a = (((a)<(b)) ? (b) : (a))
#define CHMIN(a, b) a = (((a)>(b)) ? (b) : (a))
#define EXCEPTION(msg) throw std::string("Exception : " msg " [ in ") + __func__ + " : " + std::to_string(__LINE__) + " lines ]"
#define TRY(cond, msg) try {if (cond) EXCEPTION(msg);}catch (std::string s) {std::cerr << s << std::endl;}

#define int ll
using ll = long long;
using ull = unsigned long long;
constexpr int INFINT = 1 << 30;                          // 1.07x10^ 9
constexpr int INFINT_LIM = (1LL << 31) - 1;              // 2.15x10^ 9
constexpr ll INFLL = 1LL << 60;                          // 1.15x10^18
constexpr ll INFLL_LIM = (1LL << 62) - 1 + (1LL << 62);  // 9.22x10^19
constexpr double EPS = 1e-9;
constexpr int MOD = 1000000007;
constexpr double PI = 3.141592653589793238;

using big = std::bitset<150>;

big toBig(ll n) {
	big res;
	REP(i, res.size()) {
		res[i] = n & 1;
		n >>= 1;
	}
	return res;
}

ll toNum(big n) {
	ll res = 0;
	REP(i, n.size()) {
		res += n[i] * std::pow(2, i);
	}
	return res;
}

big plus(const big& a, const big& b) {
	big res;
	res[0] = a[0] ^ b[0];
	res[1] = a[0] & b[0];
	FOR(i, 1, a.size()) {
		if (i != a.size() - 1) res[i + 1] = (a[i] & b[i]) | (b[i] & res[i]) | (res[i] & a[i]);
		res[i] = res[i] ^ a[i] ^ b[i];
	}
	return res;
}

big minus(const big& a, big b) {
	big res;
	b.flip();
	big t;
	t[0] = 1;
	b = plus(b, t); // 2の補数
	res = plus(a, b);
	return res;
}

big mul(const big& a, const big& b) {
	big res;
	REP(i, b.size() / 2) {
		if (b[i]) {
			big t = a << i;
			res = plus(res, t);
		}
	}
	return res;
}

bool compGeq(const big& a, const big& b) {
	if (a == b) return true;
	RREP(i, a.size()) {
		if (a[i] && !b[i]) return true;
		if (!a[i] && b[i]) return false;
	}
}

big mod(const big& a, const big& b) {
	big n(a), d(b);
	big m, q;
	m[0] = 1;
	while (compGeq(n, d)) {
		d <<= 1;
		m <<= 1;
	}
	big t;
	t[0] = 1;
	while (!compGeq(t, m)) {
		d >>= 1;
		m >>= 1;
		if (compGeq(n, d)) {
			n = minus(n, d);
			q |= m;
		}
	}
	return n;
}

big gcd(big a, big b) {
	big t;
	return b == t ? a : gcd(b, mod(a, b));
}

signed main() {
	INIT;
	VAR(ll, a, b);
	big A = toBig(a);
	big B = toBig(b);
	big s = plus(A, B);
	big p = mul(A, B);
	if (compGeq(s, p)) std::swap(s, p);
	big g = gcd(p, s);
	OUT(toNum(g))BR;

	return 0;
}