from collections import Counter

N=int(eval(input()))

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

B=Counter(A)

if N==len(B):

	print('YES')

else:

	print('NO')
from collections import Counter

N=int(eval(input()))

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

B=Counter(A)

if len(A)==len(B):

	print('YES')

else:

	print('NO')
from collections import Counter

N = int(eval(input()))
A = list(map(int, input().split()))
B = Counter(A)
if N == len(B):
    print("YES")
else:
    print("NO")

from collections import Counter

N = int(eval(input()))
A = list(map(int, input().split()))
B = Counter(A)
if len(A) == len(B):
    print("YES")
else:
    print("NO")

-if N == len(B): +if len(A) == len(B):