import collections

N = int(input())
A = list(map(int, input().split()))

cs = collections.Counter(A)
mcs = cs.most_common()
cnt = mcs[0][1]
if cnt == 1:
    print('YES')
else:
    print('NO') import collections collections N = int(input()) N int(input()) int input() input A = list(map(int, input().split())) A list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split cs = collections.Counter(A) cs collections.Counter(A) collections.Counter collections Counter A mcs = cs.most_common() mcs cs.most_common() cs.most_common cs most_common cnt = mcs[0][1] cnt mcs[0][1] [0] mcs 0 1 if cnt == 1:
    print('YES')
else:
    print('NO') cnt == 1 cnt 1 print('YES') print 'YES' print('NO') print 'NO' cs = collections.Counter(A) collections.Counter(A) cs N = int(input()) int(input()) N mcs = cs.most_common() cs.most_common() mcs cnt = mcs[0][1] mcs[0][1] cnt A = list(map(int, input().split())) list(map(int, input().split())) A
import collections

N = int(input())
A = list(map(int, input().split()))

cs = collections.Counter(A)
mcs = cs.most_common()
cnt = mcs[0][1]
if cnt == 1:
    print('YES')
else:
    print('NO')