#include <bits/stdc++.h>
// #include "bits/stdc++.h"

#define pout(n)  printf ("%d\n", n)

#define rep(i,a,n) for (int i = a;i < n;i++)
#define per(i,n,a) for (int i = n-1;i >= a;i--)

const int d4x[4] = {1, 0, -1, 0};
const int d4y[4] = {0, 1, 0, -1};
const int d8x[8] = { 1,1,0,-1,-1,-1,0,1 };
const int d8y[8] = { 0,1,1,1,0,-1,-1,-1 };

typedef long long ll;
using namespace std;

int main() {
  int n;
  cin >> n;

  ll x[n];

  rep(i,0,n){
    cin >> x[i];
  }
  sort(x,x+n);

  ll ans = 1000000;
	rep(i,0,n-1){
		if(x[i] == x[i+1]) continue;
		ans = min(ans,x[i+1]-x[i]);
	}
	if(0 < ans && ans <= 30) ans = 0;
  printf("%lld\n",ans);
  return 0;
}