import numpy as np
N = int(input())
if N != len(set(list(map(int,input().split())))):
    print("NO")
else:
    print("YES") import numpy as np numpy N = int(input()) N int(input()) int input() input if N != len(set(list(map(int,input().split())))):
    print("NO")
else:
    print("YES") N != len(set(list(map(int,input().split())))) N len(set(list(map(int,input().split())))) len set(list(map(int,input().split()))) set list(map(int,input().split())) list map(int,input().split()) map int input().split() ().split () input split print("NO") print "NO" print("YES") print "YES" N = int(input()) int(input()) N
import numpy as np
N = int(input())
if N != len(set(list(map(int,input().split())))):
    print("NO")
else:
    print("YES")
