stdin = gets.chomp.split(" ").map {|i| i.to_i}

n = stdin[0]
k = stdin[1]

result = ""
if n%2 == 0
if n/2 >= k
result = "YES"
else
result = "NO"
end
else
if (n/2+1) >= k
result = "YES"
else
result = "NO"
end
end

print(result)