# -*- coding:utf-8 -*-
calc_difference = lambda xi, xj: xj - xi
if __name__ == '__main__':
    n = int(input())
    xn = tuple(sorted(set(map(int, input().split()))))
    if len(xn) < 2:
        print(0)
    else:
        print(min(map(calc_difference, xn[:-1], xn[1:])))