#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
 
using namespace std;
 
#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(int i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
 
#define MOD 1000000009

vector<int> uf, usz;
int nc;

void init(int n){
  vector<int> uf_(n);
  vector<int> usz_(n, 1);
  uf = uf_;
  usz = usz_;
  nc = n;

  for(int i = 0; i < uf.size(); i++){
    uf[i] = i;
  }
}

int find(int a){
  return (uf[a] == a) ? a : uf[a] = find(uf[a]);
}

void union_(int a, int b){
  a = find(a);
  b = find(b);

  if(a != b){
    if(usz[a] >= usz[b]){
      swap(a, b);
    }
    uf[a] = b;
    usz[b] += usz[a];
    nc--;
  }
}

int check(int a, int b){
  return (find(a) == find(b)) ? 1 : 0;
}

int get_size(int a){
  return usz[find(a)];
}

int main(){
  int a,b;
  cin >> a >> b;
  int w = min(a,b);
  int h = max(a,b);
  init((w+h)*2);
  rep(i,0,h){
    if(0<=i-w){
      union_(i,h+i-w);
      union_(h+i,i-w);
    }
    if(i+w<h){
      union_(i,h+i+w);
      union_(h+i,i+w);
    }
  }
  rep(i,0,w){
    union_(h*2+i,i);
    union_(h*2+i,h+w-1-i);
    union_(h*2+w+i,w-1-i);
    union_(h*2+w+i,h+h+i-w);
  }
  cout << nc << endl;
  return 0;
}