N=int(input())
from collections import Counter
if max(Counter([int(x) for x in input().split()]).values())==1:
  print("YES")
else:
  print("NO") N=int(input()) N int(input()) int input() input from collections import Counter if max(Counter([int(x) for x in input().split()]).values())==1:
  print("YES")
else:
  print("NO") max(Counter([int(x) for x in input().split()]).values())==1 max(Counter([int(x) for x in input().split()]).values()) max Counter([int(x) for x in input().split()]).values() ([int(x) for x in input().split()]).values ([int(x) for x in input().split()]) Counter [int(x) for x in input().split()] values 1 print("YES") print "YES" print("NO") print "NO" N=int(input()) int(input()) N
N=int(input())
from collections import Counter
if max(Counter([int(x) for x in input().split()]).values())==1:
  print("YES")
else:
  print("NO")