package main

import (
	"fmt"
	"sort"
)

func main() {
	var n int
	var x []int
	maxsize := 0
	dic := map[int]struct{}{}

	fmt.Scan(&n)
	for range make([]struct{}, n) {
		var y int
		fmt.Scan(&y)
		if _, ok := dic[y]; !ok {
			maxsize = max(y, maxsize)
			x = append(x, y)
		}
		dic[y] = struct{}{}
	}
	sort.Ints(x)
	ans := maxsize
	for i := range make([]struct{}, len(x)-1) {
		ans = min(ans, x[i+1]-x[i])
	}
	fmt.Println(ans)
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}