#!/usr/bin/perl

use strict;
use warnings;

my $n = <>;
my $str = <>;
chomp $str;
my @array = split / /, $str;
my $ans = $array[1] - $array[0];
@array = sort {$a <=> $b} @array;
if($n < 3) {
	print "0\n";
} else {
	for(my $i = 0; $i < $n - 1; $i++) {
		my $com = $array[$i + 1] - $array[$i];
		if(($com < $ans)and($com > 0)) {
			$ans = $com;
		}
	}
	print "$ans\n";
}

exit;