N = int(input())
A = [int(x) for x in input().split()]

if len(set(A)) == len(A) :
    print("YES")
else :
    print("NO") N = int(input()) N int(input()) int input() input int(x) for x in input().split() for x in input().split() x input().split() ().split () input split for x in input().split() int(x) int x A = [int(x) for x in input().split()] A [int(x) for x in input().split()] if len(set(A)) == len(A) :
    print("YES")
else :
    print("NO") len(set(A)) == len(A) len(set(A)) len set(A) set A len(A) len A print("YES") print "YES" print("NO") print "NO" N = int(input()) int(input()) N A = [int(x) for x in input().split()] [int(x) for x in input().split()] A
N = int(input())
A = [int(x) for x in input().split()]

if len(set(A)) == len(A) :
    print("YES")
else :
    print("NO")