from collections import Counter
N = map(int, input().split())
A = list(map(int, input().split()))
dic=Counter(A)
for val in dic.values():
    if val > 1:
        print("NO")
        exit()

print("YES") from collections import Counter N = map(int, input().split()) N map(int, input().split()) map int input().split() ().split () input split A = list(map(int, input().split())) A list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split dic=Counter(A) dic Counter(A) Counter A for val in dic.values():
    if val > 1:
        print("NO")
        exit() val dic.values() dic.values dic values if val > 1:
        print("NO")
        exit() val > 1 val 1 print("NO") print "NO" exit() exit print("YES") print "YES" N = map(int, input().split()) map(int, input().split()) N dic=Counter(A) Counter(A) dic A = list(map(int, input().split())) list(map(int, input().split())) A
from collections import Counter
N = map(int, input().split())
A = list(map(int, input().split()))
dic=Counter(A)
for val in dic.values():
    if val > 1:
        print("NO")
        exit()

print("YES")