#include <iostream>
#include <string>
#include <vector>
#include <set>
#include <cmath>
#include <algorithm>
#include <iomanip>
#include <queue>
using ll = long long;
using namespace std;

ll GCD(ll a, ll b)
{
    if (b == 0)
        return a;
    return GCD(b, a % b);
}
int main(void)
{
    ll A, B;
    cin >> A >> B;

    if (A < B)
        swap(A, B);

    cout << GCD(A, B) << endl;

    return 0;
}