n,*a=map(int,open(0).read().split());print("YES"if len(set(a))==n else "NO") 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 print("YES"if len(set(a))==n else "NO") print "YES"if len(set(a))==n else "NO" len(set(a))==n len(set(a)) len set(a) set a n "YES" "NO" n,*a=map(int,open(0).read().split()) map(int,open(0).read().split()) n
n,*a=map(int,open(0).read().split());print("YES"if len(set(a))==n else "NO")