#include <bits/stdc++.h>
using namespace std;
#define ll long long

ll n;
ll a[1100000];
ll ans;

ll getgcd(ll aa,ll bb){
	while (bb){
		aa%=bb;
		swap(aa,bb);
	}
	return aa;
}

int main(){
	freopen("progression.in","r",stdin);
	freopen("progression.out","w",stdout);
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	cin>>n;
	for (int i=1;i<=n;i++){
		cin>>a[i];
	}
	sort(a+1,a+n+1);
	if (n<2){
		cout<<0<<'\n'; 
		return 0;
	}
	ans=a[2]-a[1];
	for (int i=3;i<=n;i++){
		ans=getgcd(ans,a[i]-a[i-1]);
	}
	cout<<ans<<'\n';
	return 0;
}