from collections import Counter

N,*A = map(int, open(0).read().split())
ac = Counter(A)
if len(ac) == N:
    print('YES')
else:
    print('NO') from collections import Counter N,*A = map(int, open(0).read().split()) N map(int, open(0).read().split()) map int open(0).read().split() (0).read().split (0).read() (0).read (0) open 0 read split *A A ac = Counter(A) ac Counter(A) Counter A if len(ac) == N:
    print('YES')
else:
    print('NO') len(ac) == N len(ac) len ac N print('YES') print 'YES' print('NO') print 'NO' N,*A = map(int, open(0).read().split()) map(int, open(0).read().split()) N ac = Counter(A) Counter(A) ac
from collections import Counter

N,*A = map(int, open(0).read().split())
ac = Counter(A)
if len(ac) == N:
    print('YES')
else:
    print('NO')