// 32351ZN
#include <iostream>
#include <sstream>
#include <vector>
#include <algorithm>
#include <complex>
#include <list>
#include <cmath>
#include <climits>
#include <cstdlib>

using namespace std;

typedef vector<int> ivec_t;
typedef vector<ivec_t> imat_t;

#define FOR_EACH(p,q,r) for(p=q;p!=r;p++)
#define FOR_EACH_C(p,c) for(p=(c).begin();p!=(c).end();p++)

int Solve(ivec_t& blanks)
{
    while(blanks.size() > 1)
    {
	int n=blanks.size();
	if(blanks[n-1] < blanks[n-2])
	{
	    blanks[n-2] %= blanks[n-1];
	    if(blanks[n-2] == 0)blanks.erase(blanks.begin()+n-2);
	}
	else if(blanks[n-1] == blanks[n-2])
	{
	    blanks.pop_back();
	}
	else
	{
	    blanks[n-1] %= blanks[n-2];
	    if(blanks[n-1] == 0)blanks.pop_back();
	}
    }
    return blanks.back();
}

int main()
{
    int n;
    cin >> n;
    ivec_t blanks(n);
    while(n--)
    {
	cin >> blanks[n];
    }
    cout << Solve(blanks) << endl;
    return 0;
}