# import itertools
# import math
# import sys
import numpy as np

N = int(input())
# S = input()
# n, *a = map(int, open(0))
# N, K = map(int, input().split())
# A = list(map(int, input().split()))
# Q = list(map(int, input().split()))
# S = input()


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

print('YNEOS'[len(A) != len(np.unique(A))::2]) import numpy as np numpy N = int(input()) N int(input()) int input() input A = np.array(list(map(int, input().split()))) A np.array(list(map(int, input().split()))) np.array np array list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split print('YNEOS'[len(A) != len(np.unique(A))::2]) print 'YNEOS'[len(A) != len(np.unique(A))::2] 'YNEOS' len(A) != len(np.unique(A))::2 len(A) != len(np.unique(A)) len(A) len A len(np.unique(A)) len np.unique(A) np.unique np unique A 2 N = int(input()) int(input()) N A = np.array(list(map(int, input().split()))) np.array(list(map(int, input().split()))) A
# import itertools
# import math
# import sys
import numpy as np

N = int(input())
# S = input()
# n, *a = map(int, open(0))
# N, K = map(int, input().split())
# A = list(map(int, input().split()))
# Q = list(map(int, input().split()))
# S = input()


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

print('YNEOS'[len(A) != len(np.unique(A))::2])