from collections import Counter

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

ac = Counter(a)
if len(ac) == n:
    print("YES")
else:
    print("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 ac = Counter(a) ac Counter(a) Counter a if len(ac) == n:
    print("YES")
else:
    print("NO") len(ac) == n len(ac) len ac n print("YES") print "YES" print("NO") print "NO" a = list(map(int, input().split())) list(map(int, input().split())) a ac = Counter(a) Counter(a) ac n = int(input()) int(input()) n
from collections import Counter

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

ac = Counter(a)
if len(ac) == n:
    print("YES")
else:
    print("NO")
