#include<iostream>
#include<string>
#include <typeinfo>
#include <fstream>
using namespace std;

template<typename T>
T get(const string &prompt)
{
    cout<<prompt;
    T ret;
    cin>>ret;
    return ret;
}
class Animal{
    string name;
    int age=7;
    float foodLevel=50;
public:
    void setName(string x){name=x;}
    string getName(){return name;}
    int getAge(){return age;}
    float getFoodLevel(){return foodLevel;}
    void feed(float x){foodLevel+=x;}
};

int cmmdc(int a,int b)
{
    if(a==1) return 0;
    if(a==b) return a;
    if(a>b) return cmmdc(a-b,b);
    return cmmdc(a,b-a);
}

int main()
{
    ifstream cinF;
    ofstream coutF;
    cinF.open("input");
    coutF.open("output");

    int a,b;
    cinF>>a;cinF>>b;
    coutF<<cmmdc(a,b);
}