n = int(input())
a = [int(s) for s in input().split()]
if len(set(a)) == n:
    print("YES")
else:
    print("NO") n = int(input()) n int(input()) int input() input int(s) for s in input().split() for s in input().split() s input().split() ().split () input split for s in input().split() int(s) int s a = [int(s) for s in input().split()] a [int(s) for s in input().split()] if len(set(a)) == n:
    print("YES")
else:
    print("NO") len(set(a)) == n len(set(a)) len set(a) set a n print("YES") print "YES" print("NO") print "NO" a = [int(s) for s in input().split()] [int(s) for s in input().split()] a n = int(input()) int(input()) n
n = int(input())
a = [int(s) for s in input().split()]
if len(set(a)) == n:
    print("YES")
else:
    print("NO")