#include <iostream>
#include <vector>
using namespace std;

int main() {
	int n, x, min, temp;
	vector< int > table(1000001, 0);
	
	cin >> n;
	for(int i=0;i<n;++i){
		cin >> x;
		table[x] = 1;
	}
	
	temp = -1;
	min = -1;
	for(int i=0;i<=1000000;++i){
		if(table[i]){
			if(temp != -1){
				if(min == -1 || min > i - temp){
					min = i - temp;
				}
			}
			temp = i;
		}
	}
	if(min == -1)min = 0;
	cout << min << endl;
	
	return 0;
}