# -*- coding: utf-8 -*-

N = int(input())
a = list(map(int, input().split()))
a = sorted(a)

pp = a.pop(0)
p = a.pop(0)
flag = True
for x in a:
    if x - p != pp:
        flag = False
        break
    pp = p
    p = x

if flag:
    print("Yes")
else:
    print("No")