import sys
import math
import itertools
import bisect
from copy import copy
from collections import deque,Counter
from decimal import Decimal
import functools
def s(): return input()
def k(): return int(input())
def S(): return input().split()
def I(): return map(int,input().split())
def X(): return list(input())
def L(): return list(input().split())
def l(): return list(map(int,input().split()))
def lcm(a,b): return a*b//math.gcd(a,b)
sys.setrecursionlimit(10 ** 9)
mod = 10**9+7
cnt = 0
ans = 0
inf = float("inf")

n = k()
a = l()

a = list(set(a))
if len(a) == n:
    print("YES")
else:
    print("NO") import sys sys import math math import itertools itertools import bisect bisect from copy import copy from collections import deque,Counter from decimal import Decimal import functools functools def s(): return input() s def k(): return int(input()) k def S(): return input().split() S def I(): return map(int,input().split()) I def X(): return list(input()) X def L(): return list(input().split()) L def l(): return list(map(int,input().split())) l def lcm(a,b): return a*b//math.gcd(a,b) lcm a a b b sys.setrecursionlimit(10 ** 9) sys.setrecursionlimit sys setrecursionlimit 10 ** 9 10 9 mod = 10**9+7 mod 10**9+7 10**9 10 9 7 cnt = 0 cnt 0 ans = 0 ans 0 inf = float("inf") inf float("inf") float "inf" n = k() n k() k a = l() a l() l a = list(set(a)) a list(set(a)) list set(a) set a if len(a) == n:
    print("YES")
else:
    print("NO") len(a) == n len(a) len a n print("YES") print "YES" print("NO") print "NO" a = l() l() a def k(): return int(input()) def k(): return int(input()) k def lcm(a,b): return a*b//math.gcd(a,b) def lcm(a,b): return a*b//math.gcd(a,b) lcm a = list(set(a)) list(set(a)) a mod = 10**9+7 10**9+7 mod def S(): return input().split() def S(): return input().split() S def s(): return input() def s(): return input() s def X(): return list(input()) def X(): return list(input()) X def L(): return list(input().split()) def L(): return list(input().split()) L cnt = 0 0 cnt ans = 0 0 ans n = k() k() n def I(): return map(int,input().split()) def I(): return map(int,input().split()) I def l(): return list(map(int,input().split())) def l(): return list(map(int,input().split())) l inf = float("inf") float("inf") inf
import sys
import math
import itertools
import bisect
from copy import copy
from collections import deque,Counter
from decimal import Decimal
import functools
def s(): return input()
def k(): return int(input())
def S(): return input().split()
def I(): return map(int,input().split())
def X(): return list(input())
def L(): return list(input().split())
def l(): return list(map(int,input().split()))
def lcm(a,b): return a*b//math.gcd(a,b)
sys.setrecursionlimit(10 ** 9)
mod = 10**9+7
cnt = 0
ans = 0
inf = float("inf")

n = k()
a = l()

a = list(set(a))
if len(a) == n:
    print("YES")
else:
    print("NO")
