n=int(input())
a=list(map(int,input().split()))
a.sort()
t=0
for i in range(1,n):
    if a[i]==a[i-1]:
        t+=1
if t==0:
    print("YES")
else:
    print("NO") 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 a.sort() a.sort a sort t=0 t 0 for i in range(1,n):
    if a[i]==a[i-1]:
        t+=1 i range(1,n) range 1 n if a[i]==a[i-1]:
        t+=1 a[i]==a[i-1] a[i] a i a[i-1] a i-1 i 1 t+=1 t 1 if t==0:
    print("YES")
else:
    print("NO") t==0 t 0 print("YES") print "YES" print("NO") print "NO" a=list(map(int,input().split())) list(map(int,input().split())) a t+=1 1 t t=0 0 t n=int(input()) int(input()) n
n=int(input())
a=list(map(int,input().split()))
a.sort()
t=0
for i in range(1,n):
    if a[i]==a[i-1]:
        t+=1
if t==0:
    print("YES")
else:
    print("NO")