#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; 

}