#include <iostream>
#include <vector>
#include <map>
#include <unordered_map>
#include <queue>
#include <set>
#include <algorithm>
#include <string>
#include <math.h>
#include <limits.h>
#include <stack>
#include <complex>
#include <stdlib.h>
#include <stdio.h>
#include <functional>
#include <cfloat>
#include <math.h>
#include <numeric>
#include <string.h>
#include <sys/time.h>
#include <random>


#define fs first
#define sc second

using namespace std;

typedef long long ll;
typedef unsigned int uint;
typedef pair<ll, ll> P;

// a と b の最大公約数を返す
ll gcd(ll a, ll b) {
    if (b == 0) return a;
    else return gcd(b, a % b);
}


ll lcm(ll a, ll b){
    return a / gcd(a, b) * b;
}



// 素数判定
bool is_prime(ll N) {
    if (N == 1) return false;
    for (ll i = 2; i * i <= N; ++i) {
        if (N % i == 0) return false;
    }
    return true;
}


// 約数列挙
vector<ll> enum_divisors(ll N) {
    vector<ll> res;
    for (ll i = 1; i * i <= N; ++i) {
        if (N % i == 0) {
            res.push_back(i);
            if (N/i != i) res.push_back(N/i);
        }
    }
    sort(res.begin(), res.end());
    return res;
}


// 素因数分解
vector<pair<ll, ll>> prime_factorize(ll N){
    vector<pair<ll, ll>> res;
    for(ll i = 2; i * i <= N; i++){
        if(N % i != 0)  continue;
        ll ex = 0;

        while(N % i == 0){
            ex++;
            N /= i;
        }

        res.push_back({i, ex});
    }

    if(N != 1)  res.push_back({N, 1});
    return res;
};



int main(){
    ll a, b;    cin >> a >> b;
    cout << gcd(a, b) << endl;

    return 0;
}