from collections import Counter

n = int(input())
a = list(map(int, input().split()))
re = 0

c = Counter(a)
new = c.values()

for i in new:
    if i > 1:
        re += 1

if re > 0:
    print("NO")
else:
    print("YES") from collections import Counter n = int(input()) n int(input()) int input() input a = list(map(int, input().split())) a list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split re = 0 re 0 c = Counter(a) c Counter(a) Counter a new = c.values() new c.values() c.values c values for i in new:
    if i > 1:
        re += 1 i new if i > 1:
        re += 1 i > 1 i 1 re += 1 re 1 if re > 0:
    print("NO")
else:
    print("YES") re > 0 re 0 print("NO") print "NO" print("YES") print "YES" n = int(input()) int(input()) n new = c.values() c.values() new re += 1 1 re a = list(map(int, input().split())) list(map(int, input().split())) a c = Counter(a) Counter(a) c re = 0 0 re
from collections import Counter

n = int(input())
a = list(map(int, input().split()))
re = 0

c = Counter(a)
new = c.values()

for i in new:
    if i > 1:
        re += 1

if re > 0:
    print("NO")
else:
    print("YES")
