#!/usr/bin/env python3
#fileencoding: utf-8

N = int(input())
X = [int(i) for i in input().strip().split(" ")]

dmin = 10e10
for i in range(N-1):
    for j in range(i+1,N):
        if X[i] == X[j]:
            continue
        tmp = abs(X[i]-X[j])
        if tmp > dmin:
            break
        else:
            dmin = abs(X[i]-X[j])
print(dmin)