#include <bits/stdc++.h>

using namespace std;

using ll =long long;
ll gcd (ll a,ll b){

if(b==0){
return a;
}
return gcd (b,a%b);


}



int main(){
ll a,b; //主函数力还得定义
cin>>a>>b;
cout<< gcd(a,b) <<endl;


return 0;
}