<?php
$n = trim(fgets(STDIN));
$num = explode(" ", trim(fgets(STDIN)));
// $num = array_unique($number);
sort($num);
// print_r($num);
$array = array();
$ans = 0;
$ans2 = 0;
for ($i = 0; $i < $n - 1; $i++) {
     $number = $num[$i+1] - $num[$i];
     if($number > 0){
        $array[] = $number;
        $ans = min($array);
     } else {
         $ans2 = $number;
     }
}
if(is_null($array)){
    echo $ans2;
} else {
    echo $ans;
}