from collections import Counter
input()
cnt=Counter(map(int,input().split()))

for v in cnt.values():
    if v>1:
        print('NO')
        break
else:
    print('YES') from collections import Counter input() input cnt=Counter(map(int,input().split())) cnt Counter(map(int,input().split())) Counter map(int,input().split()) map int input().split() ().split () input split for v in cnt.values():
    if v>1:
        print('NO')
        break
else:
    print('YES') v cnt.values() cnt.values cnt values if v>1:
        print('NO')
        break v>1 v 1 print('NO') print 'NO' break print('YES') print 'YES' cnt=Counter(map(int,input().split())) Counter(map(int,input().split())) cnt
from collections import Counter
input()
cnt=Counter(map(int,input().split()))

for v in cnt.values():
    if v>1:
        print('NO')
        break
else:
    print('YES')