from collections import Counter
n = int(input())
a = list(map(int, input().split()))
d = Counter(a)
k = d.most_common(1)[0][1]
if k>=2:
  print('NO')
else:
  print('YES') from collections import Counter 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 d = Counter(a) d Counter(a) Counter a k = d.most_common(1)[0][1] k d.most_common(1)[0][1] [0] d.most_common(1) d.most_common d most_common 1 0 1 if k>=2:
  print('NO')
else:
  print('YES') k>=2 k 2 print('NO') print 'NO' print('YES') print 'YES' n = int(input()) int(input()) n k = d.most_common(1)[0][1] d.most_common(1)[0][1] k d = Counter(a) Counter(a) d a = list(map(int, input().split())) list(map(int, input().split())) a
from collections import Counter
n = int(input())
a = list(map(int, input().split()))
d = Counter(a)
k = d.most_common(1)[0][1]
if k>=2:
  print('NO')
else:
  print('YES')