#include <iostream>
#include <stdlib.h>
using namespace std;

int main(){
	int n;
	cin>>n;
	int x[n];
	int absv = 1000000;
	int abst;
int j;
cin>>x[0];
	for (int i = 1; i < n ; ++i)
	{
		cin>>x[i];
		for (j = 0; j <= i-1; ++j)
		{
			if(x[i] == x[j]){
				if(i == j){
					continue;
				}
				cout<<"0"<<endl;
				return 0;
			}
			abst=abs(x[i]-x[j]);
			if( abst <= absv ){
				absv = abst;
			}
			if(absv == 1){
				cout<<"1"<<endl;
				return 0;
			}
		}
	}
		cout<<absv<<endl;

}