#include <iostream>

using namespace std;

int gcd(int a, int b)
{
	int res;
	while(b)
	{
		res = b;
		b = a % b;
		a = res;
	}
	return res;
}
int gcd4(int a, int b, int c, int d)
{
	return gcd(gcd(gcd(a,b),c),d);
}


int main()
{
/*	int a,b,c,d;
	cin >> a;
	cin >> b;
	cin >> c;
	cin >> d;
	cout << gcd4(a,b,c,d) << endl;
	return 0;*/

}