import algorithm
import sequtils
import strutils

const inf = high(int)

let N = parseInt(readline(stdin))
var m = 0
if N != 1:
    let Xs = sorted(map(readline(stdin).split(), parseInt), cmp[int])
    m = inf
    var p = Xs[0]
    var d = 0
    for i in 1 .. Xs.len - 1:
        let x = Xs[i]
        d = x - p
        if d != 0 and d < m:
            m = d
        p = x
    if m == inf:
        m = 0
echo m