from collections import Counter

n = int(input())
a = list(map(int, input().split()))

c = Counter(a)
d = sorted(list(c.values()))
print('YES' if d[-1] == 1 else 'NO') 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 c = Counter(a) c Counter(a) Counter a d = sorted(list(c.values())) d sorted(list(c.values())) sorted list(c.values()) list c.values() c.values c values print('YES' if d[-1] == 1 else 'NO') print 'YES' if d[-1] == 1 else 'NO' d[-1] == 1 d[-1] d -1 1 'YES' 'NO' n = int(input()) int(input()) n a = list(map(int, input().split())) list(map(int, input().split())) a d = sorted(list(c.values())) sorted(list(c.values())) d c = Counter(a) Counter(a) c
from collections import Counter

n = int(input())
a = list(map(int, input().split()))

c = Counter(a)
d = sorted(list(c.values()))
print('YES' if d[-1] == 1 else 'NO')